I do not know exactly when or how it got the virus but I have noticed it running a bit slower but I had attributed it to getting full and occaisionally it would not boot correctly (i.e system errors on start up) I run McAfee Total Protection suite and Spy-Bot every 3 days and until yesterday, nothing has shown up. Yesterday, it opened up the XP-AntiSpyware-2009 thing, which I knew I did not have so I immediately locked the firewall down, unplugged the network cable and dsl and ran a virus scan and Spy-bot scan.
They found Generic downloader.z, Spy-Agent.bw!rootkit and Memory/NTQueryDirectoryFile plus a host of other spyware items that Spy-Bot supposedly fixed. I went to McAfee's website and researched the rootkit removal process and followed it exactly three times but as soon as I rebooted, it was back. Finally, I went into XP settings and turned off the System Restore point option and scanned again. McAfee came back clean after that. Spybot showed 8 errors, one of which said something about "firewall bypass" and supposedly fixed them again. Reboot, and so far, all comes back clean on both. It's still unplugged from network and internet until I can verify it is truly clean.
How can I be 100% certain the machine is completely clean? All our business accounting software and client info is on the desktop so I have to be sure it's completely gone before I put it back on the network and online. If it means completely wiping the entire system, I'd rather do that than gamble it's still infected.