The TDSSKiller appears to have worked! It found C:\WINDOWS\system32\DRIVERS\ftdisk.sys and cured it on reboot. I ran Malwarebytes, which successfully updated. The log is below. Thank you very much!! Please let me know if I need to do anything else.
Malwarebytes' Anti-Malware 1.46
www.malwarebytes.orgDatabase version: 5042
Windows 5.1.2600 Service Pack 3
Internet Explorer 8.0.6001.18702
11/4/2010 8:26:01 AM
mbam-log-2010-11-04 (08-26-01).txt
Scan type: Quick scan
Objects scanned: 194353
Time elapsed: 16 minute(s), 36 second(s)
Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 0
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 0
Memory Processes Infected:
(No malicious items detected)
Memory Modules Infected:
(No malicious items detected)
Registry Keys Infected:
(No malicious items detected)
Registry Values Infected:
(No malicious items detected)
Registry Data Items Infected:
(No malicious items detected)
Folders Infected:
(No malicious items detected)
Files Infected:
(No malicious items detected)