My son’s computer is infected with Win32: Trojano-259[Trj] and I believe it has affected the Avast AV protection. It will not remove it. Is there a removal tool that will remove this Trojan? I found referance to it on the Avast page that said it is a VPS 0433-1,09.08.2004 but did not tell me how to remove it. If Avast is corrupt can I reinstall it over itself to repair it?
Hi and welcome Ron,
The most likely reason these trojans wont delete is that they lodge themselves in system files and folders .
Try running a boot time scan (open Avast!/settings/schedule boot time scan) so Avast can work on them alone and you should be able to delete them .
good luck 
Which is your Windows? 98, Me, XP?
You can boot at Safe Mode (F8 while booting) and scan with avast from there.
Can you pist the name of the file infected (and its path)?
Yes, or you try to repair your installation. Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair). You must be connected to the internet while repairing.
Or you may try using “Ewido” from www.ewido.net/en ;
this good & FREE program “specializes” in detecting and
removing trojans, worms, dialers, etc .