Need help! Please all ye antivirus heroes

Hey, I'm Ryan, I'm new to this board but I've been looking through some posts and seeing that people here are really helpful, so maybe you can help me

I have Avast! Antivirus and it seems to do a good job, but without even going on the internet one trojan keeps popping up and apparently is not being deleted properly, I'm not sure what it is doing because i see no decrease in performance, well not much of one anyways.. but id like to get rid of it. The file is called dbmngwdo.dll, here is my Hijack this! log:

Logfile of HijackThis v1.99.1
Scan saved at 12:07:08 PM, on 06/02/2008
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16574)

It would be great if you guys could help me out

 

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