Windows Logon Password Changed

Please help me! I was having problems with my computer not being able to surf the net. I was being automatically directed to “puppyboyz.com” or something similar. I was finally able to download the Avast antivirus software and it ran on reboot. I noticed that it had found hundreds (if not thousands) of Beagle viruses and I think I also saw a “Netsky” run across. Anyways, now I cannot logon to Windows. The screen with my username comes up and asks for a password. My computer is not password protected so when I hit “OK” it starts the logo and then immediately logs off. Can somebody help me?

Hi,

I assume you have Windows XP ? Home or Pro … ?

try booting to SafeMode (F8-Boot) and log-in there, or try there login as
ADMINISTRATOR
→ use blank password or get the administrator-password from Vendor/previous owner…

btw, what did you tell avast to do with the viruses… ?
Delete, move, rename… ?

It is XP Home. I tried booting both as administrator and from safe mode - same result. I told Avast to “delete all” Might there be a way around the password log-in screen? Does this problem sound at all familiar or common with any sort of virus? Before I had the Avast software I was using AVG and when I tried updating it a message popped up saying that the program had been “modified”.