Drivers Would Not Fix - Reinstalled Vedio Cards

This problem is kind of wierd I was having problems with my video card. When I went to boot up the screen would go black. New drivers would not fix the issue. So I bought the same videocard again, thinking that something was wrong with the old one. The new videocard still doesn't work, but in the process of trying to boot up it did something to the registry, so now if I try to boot up I see a blue screen which says there is a registry problem and it shuts the computer down. Getting frustrated I thought it was best to just reinstall XP - so I started the process, only when it got to which partition you tell it to use I got the same blue screen with a registry error. So now what? How can I reinstall XP I thought that when you were installing XP it was basically "running" off of the install disc, so how could the registry be effecting it?