Avast can't remove the virus

I am using avast for quite a long time. So far it was great.
Yesterday when I tried to scan one of my pendrive, it detected lots of viruses. The pendrive was from our lab, so it was bound to have tons of viruses.
The problem is avast can detect the viruses, but it can’t clear the viruses. It gets hanged on. I left the pc as it is, but the operation does not finish even after an hour.
The data on the pendrive is very important, so I can’t delete it. What is the solution to this problem? I can’t take the risk of sending the sample to you as I think it is a deadly virus.
Can you suggest me what should I do?

please post in the virus section of Avast forum: http://forum.avast.com/index.php?board=4.0

wait for essexboy to help u.

that said, i hope u backup ur pendrive data somewhere…this is because most repairing infected files are really a hit/miss thing. it may/may not work, and reinfection may occur even after apparent removal/repair of threats.