So i got this computer from my cousin till i can fix mine but idk what he has done to it

When i open the internet it will do nothing but adds upon adds then it will bring up a avg?? Program and it will do about 30 windows of it
Not quite sure what to do with it
Then on top of that it will jump my cpu useage 1-100 in seconds and will repeat all day long
People are telling me prob a virus?? But he doesnt have any firewalls etc on his computet or anything to decect etc
Is there a safe place to go to get a trial one so i can try and clean this up

You seem to be lost...

I am lost.....

Would you like help debugging an application you are developing? Otherwise, you would be better off here http://forums.d2jsp.org/forum.php?f=188 or perhaps even here http://www.google.com