What programs and techniques did you use to scan for viruses, exactly?
If you want a suggestion, here is mine: uninstall whatever antivirus you've got, install a 30-day trial of Kaspersky Antivirus Personal 5, and set it up as described
on this page for maximum protection.
Also make the preparatory steps for running
this manual McAfee scanner.
Now also download F-Secure's
BlackLight rootkit detector. Run it, use the rename option for anything that it detects as a rootkit, and promptly reboot into
Safe Mode With Command Prompt and run the manual McAfee scanner.
Once the McAfee scanner is done, do a CTRL ALT DELETE to bring up Task Manager and use the
Applications > New Task to launch
explorer.exe. Now use the Start menu to launch a full Kaspersky antivirus scan.
After that, reboot into normal Windows and run it through the Windows Update and Office Update sites to get it fully patched, if they'll let you onto the network with it.
Alternately, just use
DBAN to vaporize your Windows installation (and all other data) and then
set up Windows securely so it doesn't get infected by worms the instant you plug into the network.