avast warning virus found... and I don't know what I am meant to do...

First I apologise… I probably should know what to do, but I dont and I don’t really understand I.T related things.

I am trying to follow step 1 (do not panic) but easier said when you don’t know what you are doing and a bit scared any minute your pc will combust

I have an Avast warning come up saying ‘A Virus was found’ (I think it appeared when I was trying to pay a bill online which is why I am panicing a little)

File name I:\autorun.inf
Malware name BV:AutoRunC [Wrm]
Malware Type Virus/worm
VPS Version 091216-0 16/12/2009

It seems to recommend ‘Move to Chest’ but when I click this option I get the following message

Avast! The process cannot access the file because it is being used by another process
cannot process “I;\autorun.inf” file

I don’t know whether to switch machine off or not. I really don’t have a clue what to do. Any help given would be gratefully received but need step by step guidance due to my ignorance.

??? :-[

Did you have some external device connected at the time of the alert ?
Download this program, (v2.4)
http://oldmcdonald.wordpress.com/2009/06/02/autorun-eater-v24/
unzip it, run and install. The program is now running real time. You will see an icon that looks like an orange traffic cone in the task bar .It will search for bad autorun.inf files, let it delete what it finds. Plug in any external devices ( flash drives/hard drives, that may be infected ) These too will be searched.
When this has finished, do a boot time scan with Avast, scanning all devices.
http://www.digitalred.com/avast-boot-time.php

Then download MBAM, install,update and run a quick scan. Report the findings of all three progams

http://filehippo.com/download_malwarebytes_anti_malware/

If you have Ad-Aware PRO by Lavasoft,this may see Autorun Eater as malicious,this is a false alarm

Thank you so much for your help. I’ve done all you said, so far the scans for Avast and the last one have come back saying no malware or viruses found. I will try and reboot and see if the warning comes again.