problems with nvidia gforce fx 5500

i was installing ffxl and i was having problems with my grpahics card.. it kept restarting my pc, so heres what i did.... I uninstalled the driver and tried to reinstall it.. but now it shows that it reinstalls...but nothing.. under the display monitor theres nothing..i right click my computer and then device manager and the video controller(vga compatible) has a yellow ! mark. so i right click and update driver, so it updates then it says hardware cannot be installed.... SOMEONE PLEASE HELP ME ON THIS..

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i was installing the fx 5500 and i was having problems with my grpahics card too.. it kept restarting my pc, so heres what i did.... I uninstalled the driver and tried to reinstall it.. then it blanked my screen and even when I tried with another video card and the onboard video, it would stay blank but let the programs run (I could hear the music and sounds of them )...on the display monitor theres nothing..so then maybe my 240w power supply is too low, it does say on the box it needs atleast a 250w (on the disk it says it need atleast a 300w power supply ) but now after changing to a 400w power supply, it gives me a screen full of arrows and restarts the system .... SOMEONE PLEASE HELP ME ON THIS..I would greatly be thankful..thanks


version of windows: Windows XP Pro / 5.1.2600 SP2 Build 2600
CPU: AMD Athalon XP 2000+
motherboard make/model: Micro-Star International / KM400-8235
video card make/model: nVIDIA \ BFG G-Force FX 5500 OC
AGP 8x/4x 256MB DDR
Bios: Phoenix Tech 6.00 PG 2/16/2005