I need help installing my new video card for my computer.?

I have a HP computer and it has 128 MB integrated memory, and I bought a 256-memory card called (viper x1300) made by ATi radeon. When I installed the new memory card in the computer and started up the computer it just goes trough the booting process and few seconds later it stop all together. I don't know what is causing that. Do I need to disable or bypass the original memory card in order for the new card to work? Can someone please help me with this? Thank you|||Most likely you'll need to enter the BIOS setup screen, an opportunity that only happens when you're first turning on your computer. Watch all of the words on the screen. If you have a big HP logo that covers the screen and doesn't let you see, try hitting the Esc key to get that graphic out of the way so that you might see how to get into the BIOS setup screen. Within there, somewhere, you should find where to disable the onboard video. It might be worth a phone call to HP's support and see if they can help you find that within the BIOS. I don't own an HP so I couldn't tell you exactly how and what to do.