get this message constantly and cannot remove the offender
Scan type: Realtime Protection Scan
Event: Virus Found!
Virus name: Trojan Horse
File: C:\WINDOWS\system32\a1420e.dll
Location: C:\WINDOWS\system32
Computer: IBM-99D43157127
User: SYSTEM
Action taken: Clean failed : Quarantine failed : Access denied
Date found: Sunday, March 08, 2009 4:41:20 PM
what to do?