Today, I bought PNY geforce 8400 GS 512mb and installed to my HP a844n (specification: http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&dlc=e...). Everything went working fine when I turned on the computer, until strange thing happened during Windows XP loading. When Windows XP was loading (the one with blue bar moving horizontally and big Windows XP logo), the blue bar was moving for a few seconds then it stopped. I waited for many minutes and it hadn't progressed, it looked like it got frozen.
I checked everything from the connection and installed the driver in the safe mode, the result was still the same. I would have to assume it's either the video card failure or my 300 watt isn't supporting it. I returned the card back to the store later this evening.
I've decided to give up on trying to upgrade graphic card and stick with stockbone Intel 64mb graphic. The minimum reason for me to upgrade the graphic is to watch a DVD movie in higher quality. I got the new Samsung T260 monitor, so I would want to watch wide screen maximum with better picture quality. I know the result would be that I have to buy a new PC, but I don't have money for it.
oh so you're using the pci slot eh. afaik, pci 2400s only comes in "pro". so yeah you should get the cheapest among the bunch, problem is the cheapest one comes with passive cooling. im not a strong believer of passive cooling. i'd get the 65$ card instead.
btw if the same symptom still persist, heres what you can do:
1. fresh install the OS
2. ask a friend to have your card tested on his rig. its pci anyway.
3. update the motherboard's bios (im not familiar with that hp of yours though)