Hi, if you would like to delete a certain file that is being picked up by a Anti-Virus, I assume that your A-V tells you the file name, and where it is located, the file cannot be deleted becasue it is still in process, so goto "Start Menu", ">Run" inside the run console type in "tskill *" this will close everything including your explorer. The computer will then say "Shuting Down in xx:xx seconds", hold "Ctrl + Alt + Del" to bring up your task manager, then goto "File", then >"New Task(Run...)", then type in "shutdown -a". If your explorer has not come up after all these steps then, open "taskman" and in the "Run" type "explorer". Once all these steps have been followed locate the file on your computer and delete it. Done... and restart.
An even simpler way of deleting a file that is still in process is getting the program called "Hijackthis.exe" which you will find on this site. Open the file and then goto "Open the misc tool section" you will see under "System tools" a button saying "Delete a file on reboot..." from there you select the file and restart so that it is deleted.
When finished deleting the file, for reassurance run a Virus scan.
Hope this help. Enjoy....