troubleshooting possible video card going bad

I have a Dell Dimension 8300 that came with an ATI Radeon 9800 video card.

I am experiencing some problems recently with my display.
It started off with some blue lines flickering in and it gradually progressed to be more and more prominent. Now I am getting alternate yellow thick stripes alternating with normal colors of the screen. If I drag and drop a frame, it colors in the yellow stripes as I move across diagonally.

I tried to reset my video card, made sure the battery connector is secure and that did not help.
Also I am suddenly experiencing upon reboot, a battery voltage is low message.

I am trying to troubleshoot where the problem lies. I suspected it to be my video card but since I don't have another card available to swap it out I though I'd try a forum to get some ideas from others.

any thoughts?
Thanks