May be a bit late. Have had the same problem comm.dll, WinKA.exe
TrojanDownloader.Win32.Agent.bf
Client is running Nortons and it is up to date, full scan found nothing. Every time the PC rebooted/restarted the C:\windows\system32\autoexec.nt got deleted (windows file require for DOS based program). Have installed Kaspersky 4.5 Pro and it fixed it. Total of 8 virus's with 12 body's found. Researched and proved to the virus below.
C:\Program Files\WindUpdates\Comm.dll Infected TrojanDownloader.Win32.Agent.bf <cd0000.0.e>
C:\Program Files\WindUpdates\Comm.dll Deleted TrojanDownloader.Win32.Agent.bf <d10000.0.d>
C:\Program Files\WindUpdates\WinKA.exe Infected TrojanDownloader.Win32.Agent.bf <cd0000.0.e>
C:\Program Files\WindUpdates\WinKA.exe Deleted TrojanDownloader.Win32.Agent.bf <d10000.0.d>
