Here's the thing GC. Once you have an infection, unless you completely wipe the hard drive and re-install everything (including your OS), you can never be 100% certain it's clean. You can do a bunch of different scans (the more the better because no single program will get everything) and be reasonably sure all the crap is gone, but depending on how paranoid you are, a full wipe may be safest.
When we do malware scans here at work (I do several of them a week), it takes about five hours to complete. These are the free tools I/we use:
- AVG
- MalwareBytes
- SuperAntiSpyware
This has some pop-up warnings you may find annoying, but does a good clean-up job.
- SpyBot Search & Destroy
- Microsoft Malicious Software Removal Tool
You may have this already if you do Windows Updates regularly. Just go to the Start menu then click "Run".
In that dialog, type "mrt" then click [OK]. If the program runs, make sure you have the current version (it's updated once a month) as noted on the title bar. If you don't have the program or if the version you have is not current, run Windows Update manually. Open IE (yes, it MUST be IE) and select "Windows Update" from the "Tools" menu.
- Microsoft Security Essentials
I have not personally used this yet, but I have heard good things about it. It's free for personal use.
I'd recommend running all of these programs, rebooting after each one completes. That's what I do when I scan peoples' computers. And I do this a LOT! As I mentioned, no single program will find everything, so hitting it with multiple assaults is your best bet (short of wiping your HD and starting over) Just budget several hours for all the scans to complete. Do not use more than one program to scan at a time and always choose to do a full/complete scan as opposed to quick/partial.