Accidentally opened an infected .exe file

[MrYumYum]

Hello.
I may have accidentally opened an infected .exe file while trying to download something. After double clicking the file, it suddenly disappeared and appeared to have executed nothing.
I've used the latest Avast and Malwarebytes to scan my computer which detected nothing; how can I be certain my computer is not infected?

[SuperDave]

Hello and welcome to Computer Hope Forum. My name is Dave. I will be helping you out with your particular problem on your computer.

1. I will be working on your Malware issues. This may or may not solve other issues you have with your machine.
2. The fixes are specific to your problem and should only be used for this issue on this machine.
3. If you don't know or understand something, please don't hesitate to ask.
4. Please DO NOT run any other tools or scans while I am helping you.
5. It is important that you reply to this thread. Do not start a new topic.
6. Your security programs may give warnings for some of the tools I will ask you to use. Be assured, any links I give are safe.
7. Absence of symptoms does not mean that everything is clear.

If you can't access the internet with your infected computer you will have to download and transfer any programs to the computer you're using now and transfer them to the infected computer with a CD-RW or a USB storage device. I prefer a CD because a storage device can get infected. If you use a storage device hold the shift key down while inserting the USB storage device for about 10 secs. You will also have to transfer the logs you receive back to the good computer using the same method until we can get the computer back on-line.
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Please download AdwCleaner by Xplode onto your Desktop.

Before starting AdwCleaner, close all open programs and internet browsers, then double-click on the AdwCleaner icon.



If Windows prompts you as to whether or not you wish to run AdwCleaner, please allow it to run.
When the AdwCleaner program will open, click on the Scan button as shown below.



AdwCleaner will now start to search for malicious files that may be installed on your computer.
To remove the files that were detected in the previous step, please click on the Clean button.



AdwCleaner will now prompt you to save any open files or data as the program will need to reboot the computer. Please do so and then click on the OK button. AdwCleaner will now delete all detected adware from your computer. When it is done it will display an alert that explains what PUPs (Potentially Unwanted Programs) and Adware are. Please read through this information and then press the OK button. You will now be presented with an alert that states AdwCleaner needs to reboot your computer.
Please click on the OK button to allow AdwCleaner reboot your computer.A log will be produced. Please copy and paste this log in your next reply.
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Malwarebytes' Anti-Rootkit

Please download Malwarebytes' Anti-Rootkit and save it to your desktop.

• Be sure to print out and follow the instructions provided on that same page for performing a scan.
• Caution: This is a beta version so also read the disclaimer and back up all your data before using.
  
• When the scan completes, click on the Cleanup button to remove any threats found and reboot the computer if prompted to do so.
  
• Perform another scan with Malwarebytes Anti-Rootkit to verify that no threats remain. If they do, then click Cleanup once more and repeat the process.
  
• If there are problems with Internet access, Windows Update, Windows Firewall or other system issues, run the fixdamage tool located in the folder Malwarebytes Anti-Rootkit was run from and reboot your computer.
  
• Two files (mbar-log-YYYY-MM-DD, system-log.txt) will be created and saved within that same folder.
• Copy and paste the contents of these two log files in your next reply.

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Please download Junkware Removal Tool to your desktop.

•Warning! Once the scan is complete JRT will shut down your browser with NO warning.

•Shut down your protection software now to avoid potential conflicts.

•Temporarily disable your Antivirus and any Antispyware real time protection before performing a scan. Click this link to see a list of security programs that should be disabled and how to disable them.

•Run the tool by double-clicking it. If you are using Windows Vista or Windows 7, right-click JRT and select Run as Administrator

•The tool will open and start scanning your system.

•Please be patient as this can take a while to complete depending on your system's specifications.

•On completion, a log (JRT.txt) is saved to your desktop and will automatically open.

•Copy and Paste the JRT.txt log into your next message.

[MrYumYum]

Hello and thank you.
Here are the scan results from AdwCleaner:
# AdwCleaner v3.311 - Report created 05/10/2014 at 20:49:03
# Updated 30/09/2014 by Xplode
# Operating System : Windows 8.1 Pro  (64 bits)
# Username : Idan - IDANP
# Running from : C:\Users\Idan\Downloads\Programs\adwcleaner_3.311.exe
# Option : Clean

***** [ Services ] *****


***** [ Files / Folders ] *****


***** [ Scheduled Tasks ] *****


***** [ Shortcuts ] *****


***** [ Registry ] *****


***** [ Browsers ] *****

-\\ Internet Explorer v11.0.9600.17278


-\\ Mozilla Firefox v32.0 (x86 en-US)

[ File : C:\Users\Idan\AppData\Roaming\Mozilla\Firefox\Profiles\yz5koejh.default-1409932114898\prefs.js ]


*************************

AdwCleaner[R0].txt - [1669 octets] - [05/09/2014 19:18:20]
AdwCleaner[R1].txt - [936 octets] - [29/09/2014 08:49:17]
AdwCleaner[R2].txt - [1054 octets] - [05/10/2014 20:47:27]
AdwCleaner[S0].txt - [1536 octets] - [05/09/2014 19:49:40]
AdwCleaner[S1].txt - [996 octets] - [29/09/2014 09:02:34]
AdwCleaner[S2].txt - [977 octets] - [05/10/2014 20:49:03]

########## EOF - C:\AdwCleaner\AdwCleaner[S2].txt - [1036 octets] ##########

I've tried running the Malwarebytes Anti-Rootkit update several times; it reaches about 75% and gets back to 0% over and over for about half an hour, upon which it claims that the update failed.
What should I do?
I tried running it regardless of the updates and it found no threats.

[MrYumYum]

EDIT:
So it asked to change something in the registry at first if in case the scat/update goes awry, which i had forgotten on the first time.
With that changed, the update went well and here's the log of the new scan:
Malwarebytes Anti-Rootkit BETA 1.07.0.1012
www.malwarebytes.org

Database version: v2014.10.06.01

Windows 8.1 x64 NTFS
Internet Explorer 11.0.9600.17278
Idan :: IDANP [administrator]

10/6/2014 8:03:04 AM
mbar-log-2014-10-06 (08-03-04).txt

Scan type: Quick scan
Scan options enabled: Anti-Rootkit | Drivers | MBR | Physical Sectors | Memory | Startup | Registry | File System | Heuristics/Extra | Heuristics/Shuriken
Scan options disabled:
Objects scanned: 312404
Time elapsed: 8 minute(s), 53 second(s)

Memory Processes Detected: 0
(No malicious items detected)

Memory Modules Detected: 0
(No malicious items detected)

Registry Keys Detected: 0
(No malicious items detected)

Registry Values Detected: 0
(No malicious items detected)

Registry Data Items Detected: 0
(No malicious items detected)

Folders Detected: 0
(No malicious items detected)

Files Detected: 0
(No malicious items detected)

Physical Sectors Detected: 0
(No malicious items detected)

(end)

[MrYumYum]

And that's the one from the JRT:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Junkware Removal Tool (JRT) by Thisisu
Version: 6.3.1 (10.06.2014:1)
OS: Windows 8.1 Pro x64
Ran by Idan on Mon 10/06/2014 at 19:37:00.96
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




~~~ Services



~~~ Registry Values



~~~ Registry Keys



~~~ Files



~~~ Folders



~~~ Event Viewer Logs were cleared





~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Scan was completed on Mon 10/06/2014 at 19:40:32.46
End of JRT log
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Doesn't seems like there's a problem so far.

[SuperDave]

I'd like to scan your machine with ESET OnlineScan

•Hold down Control and click on the following link to open ESET OnlineScan in a new window.
ESET OnlineScan

•Click the button.
•For alternate browsers only: (Microsoft Internet Explorer users can skip these steps)

• Click on to download the ESET Smart Installer. Save it to your desktop.
  
• Double click on the icon on your desktop.
  

•Check
•Click the button.
•Accept any security warnings from your browser.

• Leave the check mark next to Remove found threats.
  

•Check
•Push the Start button.
•ESET will then download updates for itself, install itself, and begin scanning your computer. Please be patient as this can take some time.
•When the scan completes, push
•Push , and save the file to your desktop using a unique name, such as ESETScan. Include the contents of this report in your next reply.
•Push the button.
•Push
A log file will be saved here: C:\Program Files\ESET\ESET Online Scanner\log.txt

[MrYumYum]

ESETSmartInstaller@High as downloader log:
all ok
# product=EOS
# version=8
# OnlineScannerApp.exe=1.0.0.1
# OnlineScanner.ocx=1.0.0.7623
# api_version=3.0.2
# EOSSerial=94f87ee93b8f924bb88bddc12cf86ff5
# engine=20469
# end=finished
# remove_checked=true
# archives_checked=true
# unwanted_checked=true
# unsafe_checked=false
# antistealth_checked=true
# utc_time=2014-10-06 09:24:31
# local_time=2014-10-07 12:24:31 (+0200, Jerusalem Daylight Time)
# country="United States"
# lang=1033
# osver=6.2.9200 NT
# compatibility_mode_1='avast! Internet Security'
# compatibility_mode=781 16777213 100 97 1763464 9847895 0 0
# compatibility_mode_1=''
# compatibility_mode=5893 16776574 100 94 7437016 17014192 0 0
# scanned=203564
# found=2
# cleaned=2
# scan_time=5162
sh=4370E4F60FB96627C6AD4F4820A4FA8A61F8EC29 ft=1 fh=3b60eb1472d7e959 vn="a variant of Win32/CNETInstaller.B potentially unwanted application (deleted - quarantined)" ac=C fn="C:\Users\Idan\Downloads\Programs\cbsidlm-cbsi213-YouTube_Music_Downloader-SEO-75409715.exe"
sh=DCF2DA89215BBA07A614AC4406EC8BA17E7DA90E ft=1 fh=d9478e8f9ea0169f vn="a variant of Win32/Toolbar.Widgi.G potentially unwanted application (deleted - quarantined)" ac=C fn="C:\Users\Idan\Downloads\Programs\SetupYTD.exe"

[SuperDave]

How's your computer running now? Any other issues?

[MrYumYum]

Well there is the fact that whenever I leave my torrent client on for a long time my computer kinda starts slowing and jamming, which could be related to a virus, though this has been the case before the issue that prompted this thread. Other than that nothing out of the ordinary.

[SuperDave]

Ok. Let's do some clean up.

This step will remove all cleaning tools we used, it'll reset restore points (so you won't get reinfected by accidentally using some older restore point) and it'll make some other minor adjustments...
This is a very crucial step so make sure you don't skip it.
Download DelFix by Xplode to your desktop. Delfix will delete all the used tools and logfiles.

Double-click Delfix.exe to start the tool.
Make sure the following items are checked:

• Activate UAC (optional; some users prefer to keep it off)
• Remove disinfection tools
• Create Registry backup
• Purge System Restore Points
• Re-set system settings

Now click "Run" and wait patiently.
Once finished a logfile will be created. You don't have to attach it to your next reply.
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Click Start> Computer> right click the C Drive and choose Properties> enter
Click Disk Cleanup from there.



Click OK on the Disk Cleanup Screen.
Click Yes on the Confirmation screen.



This runs the Disk Cleanup utility along with other selections if you have chosen any. (if you had a lot System Restore points, you will see a significant change in the free space in C drive)
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I suggest using WOT - Web of Trust. WOT is a free Internet security addon for your browser. It will keep you safe from online scams, identity theft, spyware, spam, viruses and unreliable shopping sites. WOT warns you before you interact with a risky website. It's easy and it's free.

Check out Keeping Yourself Safe On The Web for tips and free tools to help keep you safe in the future.

Also see Slow Computer? It may not be Malware for free cleaning/maintenance tools to help keep your computer running smoothly.
Safe Surfing!

[MrYumYum]

Great, I'll check these out.
Many thanks.

[SuperDave]

You're welcome. I will lock this thread. If you need it re-opened, please send me a pm.