Virus detect on Device Manager click

After installing Avast 4 home, I wanted to check the status of a modem driver that I just installed. I right-clicked on My Computer => Properties, Hardware tab the Device Manager button. Immediately on clicking on the button I got a virus detect error. At the time I didn’t connect clicking on the button and getting the error. So I clicked on delete the virus. However every time I click on the Device Manager button I get a virus warning. Deleting the virus doesn’t help. Any ideas?

I suppose you’re using XP.
Can you post the name and the path of the ‘infected’ driver file?