Why does my computer keep suddenly restarting after i installed my new video card???

the video card is a MSI MX4000 128MB with a nivida processer in it i guess.. Right after I installed it i tweeked with a couple settings to make my colors look right and now it just restarts over and over again sometimes even before windows even has a chance to come up I have been up alllll night till morning trying to fix it by unstalling drivers and reinstalling them the computer is a compaq presario model 5wv254 with a amd 1.2 ghz processer in it its agp 4x and the video card is good with 8x and 4x agp slot compatible so please someone help me!!!!|||It probably needs its own seperate power source!

Your stock computer doesn't have the juice to run it|||have you unistalled the old video card program yet?.....that's the first thing you have to do.|||my HP does that too, let me know what you figure out.|||Uh- thats a virus, Sir. I doubt its anything to do with your new card.|||download the latest update from nvidia website. I think its 30+MB in size. then also update you direct X.|||Well download the lastest driver for that card try that, If same o things happens uninstall it, then remove card|||Either the video card is damaged or it's not compatible with your computer. And check your previous video card. If it's an onboard, you can't add another video card. Better unplugged it or your motherboard crashes.|||Be sure that the temperature is stable inside the computer.|||you must've had move or unplugged something inside... or check if the video card is compatible with the motherboard... you can also try starting your computer in safe mode and checking if you have the proper drivers installed or that your PC knows that is running that video card and not the old one... remember not because they have the same slot means that they are compatible.|||Go into your control panel and set the video adapter to VGA, uninstall the video drivers you loaded and the drivers for the old card. Then go to the MSI website and download the latest drivers.

http://www.msi.com.tw/program/search/ser…|||u might not have enough power