How do I pin out the suspect virus file?

From ntbtlog.txt (xp boot log file), I found out there is a driver file changed its name everytime I reboot.

Loaded driver \SystemRoot\System32\Drivers\Modem.SYS
Loaded driver \SystemRoot\System32\Drivers\a5mzjxub.SYS
Loaded driver \SystemRoot\system32\DRIVERS\cfosspeed.sys

However, when I login xp, I can't find the suspect file.
This possible virus also appears in registry (HLKM/System/CurrentControlSet/Services/), and also changes its name when I reboot.

I have used NOD32 2.7 (with updated virus code) to scan the hardrive in safe mode, but no luck.
Can anyone give me some idea and tool to pin out this virus? Thank you.

 

You can try scanning with more tools.

http://www.malwarebytes.org/
http://www.superantispyware.com/
http://www.freedrweb.com/

 

Can you confirm that you don't have the tool cFosSpeed for shaping Internet traffic installed? Also I'd recommend installing EAV v3 or v4 beta which detect more malware than v2.

 

I do have cfosspeed installed. I tried Nod32 4 RC and scaned in windows. No virus catched. And I tried avira antivir and scaned in safe mode. No virus catched.
From ntbtlog.txt, I see that the virus runs early than avira and nod32.
Any other suggestion?