nvidia geforce series 6 p260 flickering lines problem

Ok so i realy need alot of help here. So yeterday i took my graphics card out of my dell xsr computer to check the name of the card. The card worked fine until i did this. Then wen i hooked everything back up horizontal flickering lines poped up on my screen. This is a very good computer and i would rather not have to toss it if its just a problem with the graphics card. I dont have any computer info because i cant see through the graphical errors. But it is a windows XP computer.

Thank you.