Internet on Specific Computer Slowed Down

[Elitewarriors]

On my particular computer my internet has very recently become unreliable. speedtest.net has shown that my internet has gone from 20mb/s to about 9mb/s at best, and sometimes going to 1mb/s. This has only happened in the past week, and is not only slower at the best of times, but unreliable as well. My upload doesn't seem to have changed much.

I am using wireless and other computers on my network are getting the typical speed of 20mb/s so I'm confident that it's only my computer. I am also the only PC in this Mac infested house however, but i'm pretty sure that's not the problem considering this has only happened recently.

I uninstalled a few programs and that seemed to have helped a bit, one in particular seemed to make a noticeable difference. It could possibly be my processor since i've been having some problems with it but i'm not confident that it would result in the recent problems and the only reason I bring it up is to try and consider everything. I have more I could guess at but I'm rather confident they aren't related to my current problem, so maybe just go over some more basic trouble shooting with me first, and if that doesn't work we'll look at some of my other problems.

I've already tried restarting both my modem and wireless router. I also called my ISP about a week ago in regards to a slower connection, but that was solved with just a router and modem reset. Not only that but it was a household problem, not just my machine.

Help as soon as possible would be appreciated! 

EDIT: I'm using Windows 7.

[jason2074]

The first thing you should know is that you are sharing internet connection with other computers. So a 20 mb/s will not be practically achieved. Wired connections are faster and more secured. Accumulation of junk files, temporary files and infection could also make your PC cause certain lagging. You will see the difference on these when connecting on LAN either directly on the modem or the router itself and using the connection alone.

[Rob Pomeroy]

When you say "recently" - have you tried using system restore, to take your computer back to just before you noticed this slowness?  It could be that a recent Windows update (or something like that) caused the problem.  Has anything else changed?  Have you, for example, put a baby monitor or a cordless phone in the vicinity of the Windows PC?  (Baby monitors, cordless phones, A/V senders, etc. all interfere with wireless networks.)

[Rustys]

How is the computer that is having the issue connected?

Wireless see if you can connect it to the modem or router with a cable and then see if that improves the speeds.

Wired (connected by a cable) try it wireless to see if that makes a difference.

Make sure to turn off the wireless if you are trying the wired.

Is there certain times that this happens, are others on, how many computers are connected to the network, and what are they browsing when this happening.

Is that system or any others running any P2P or Torrent?