1.
McAfee Software. Is this a security suite or just the AntiVirus? If you'll going to stay with McAfee, go ahead and install it; but the virus "definitions" will not be current. Personally, I prefer to use other "free" alternatives for home use.
Yes, you may scan the "E:" drive with whatever security software you have. You should also scan it using some AntiMalware products; e.g. MalwareBytes Anti-Malware, SuperAntiSpyware.
Get the internet connection going so you may download, install, and run the quality "free" security software that's available. This might include AntiVirus, AnitSpyware/AntiMalware, and/or Firewall software.
If you're behind a home router (using Network Address Translation software to hide your Local Area Network addresses), you should be OK long enough to download the needed software and install it (along with the Windows Updates from Microsoft). Just don't go browsing the entire World Wide Web before you get your security setup.
2.
Motherboard Drivers. Are you attempting to use a
network adapter that is integrated "onboard" the motherboard? If so, you need to install the driver for it. For that matter, I think you need to load the "chipset" drivers and all other motherboard drivers for the onboard components. Install chipset drivers first, reboot, then install the other drivers. I'm not sure if order is significant. For what it is worth, here is the order that Dell recommends:
Installing Drivers in the Correct Order.
Device Manager should indicate whether you're missing device drivers. To access:
a. Select "Start" menu button
b. Right-click "My Computer" - context menu appears
c. Select "Properties" - "System Properties" window appears
d. Select "Hardware" tab
e. Select "Device Manager" button
Look for and report any Exclamation Mark", Blue "i", Red X, or "Other Devices" category.
3.
Online Data Files. You may store them on which ever drive you wish. As I've mentioned previously, some people like to separate the operating system from the data (including "My Documents" folder) using different partitions/volumes or drives. This permits them to blow away the operating system partition and reinstall without affecting the data.
4.
Backup Data. You should always backup "data" files that you can't afford to lose (but not in the same computer). This is a "chapter" all by itself and beyond the scope of this thread.