Trojan-can't log into to accounts

[tmh88]

I'm using an itouch so i'm keeping this short.

My parents dell dimension 8300 has a Trojan and we can't log into the user accounts on xp. As soon as I try to log in it immediately logs out back to the welcome screen.

I tried to use avg anti virus, and that's when the logging out issue started. I ran it and it detected a bunch of infected files. Restated the computer and couldn't log back in. Same thing happens in safe mode.

Don't have an xp disc for system restore.

Any suggestions?
Thanks

[Katana]

AVG had a problem a while back with deleting a critical system file that caused such a situation, were you using old definitions ?

Unfortunately, without an XP disc the options are limited.

Does the machine have a Recovery Partition ?