Trojan comes back after removing it succesfuly by Avast!

Hi,
I have Avast free Home Edition. I succesfully removed a trojan 3 days ago: WIN32: SMALL-JMH [trI] on safe mode. But the trojan comes back again, even after disabling the system restoration. Also, Avast always asks me to restart the computer after a simple update. I didn’t have to do that in the past. Also, when I start the computer it says CPU fan error! Press F1 to resume. I then press F1 and it goes on Windows, but sometimes it goes to the BIOS. Maybe it has something to do with it.
Sorry, I just read Tech’s message. I will try to delete reboot file, but what about the virus that comes back?
I have a Pentium 4 3.0gig 775 64 bits with Asus P5PGL Hyperthreading (SL7Z9) and 1024 ddr ram. It runs with Windows XP.

Thanks for your help!
Bernadette2711.

i doubt that Avast would have anything to do with the Fan issue.

As for asking to restart windows this can happen depending on what files the update has updated, usually if its updated the program it asks for a restart.

Operating system restart needed by avast message could be solved, in some systems, by deleting the file \setup\reboot.txt

If deleting reboot.txt doesn’t stop the requests for reboot check this:
Check this registry entry (right after computer restart):
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager, if it contains “PendingFileRenameOperations”.
Check its contents and if there’s only “reboot.txt” from avast4\setup folder, delete PendingFileRenameOperations, don’t delete any other key.
Back-up (export) the registry key before you edit/delete, just in case.