PUP.exe Trojan?

I have been having some odd problems lately with my PC which seem to
indicate a Trojan in onboard. On startup I get a 'new' .exe appearing in my
C:\windows\system32 directory ervery time. It always has a different name
(tblfiltu.exe, ssecd.exe, hcpmond.exe, etc) but has the same date and size
(65,536). The properties of the file are also the same:
Company: tmax
Original filename: pup.exe
Product name: werule
The file (whatever it's current name) is in the registry under the
Windows/Current Version/Run section.

I have run Spybot and Ad-aware (with system restore off) to no effect.
Ad-aware finds new data miner cookies every startup though.

Does anyone know what is going on?

Regards,
David.