i bought a fx 5500 256 mb agp 8x<old> {i dont know if it supports agp 4x or not}i dont know what brand it is my motherboard is asus x series p4sgx mx agp 4x,intel celeron 1.7 ghz processor 230 w power supply.
at first when i inserted it and started my pc i got no display at all,nothing.
then i put in a 400 w psu igot display but my pc hung up, iput my 230 w psu back and start again,the card is detected,windows loaded,i installed the drivers.i restrarted a few times and the windows was still detecting the card .i tried a few games they ran but not so smoothly.but now the card works until windows loads but then stops working<monitor does not show any display>. and somtimes there is no display even when the computer is rebooting
what is the problem?
will the card work properly if i use a more powerfull psu

I believe the graphics card is agp x8 only!!!!

If your mobo is x4 only then the slot runs at 1.5 volts!!!!
If indeed you graphics card is x8 only then it runs at 0.8 volts!!!!

Im afraid you may have fried it!!!!

For more information about agp speeds have a look at this - http://en.wikipedia.org/wiki/Accelerated_Graphics_Port - and this - http://pcf.mundayweb.com/index.php?view=14&

i read somewhere else that the Video card has self voltage regulation, so it can adjust itself to the voltage needed

If the graphics card was an agp x4/x8 then that would be the case!!! However, an agp x8 only will have been designed to run at 0.8 volts only!!!!

Most x8 only cards have been designed that way to make them cheaper!!
As an example i used to have a x8 only xcalibur 9550 which was only £36 new, it failed, so i got a radeon 9550 x4/x8 which was £50 new!!!!

Yes it seems you might have fried the card. AGP x4 and x8 use different voltages and using an x8 card in an x4 mobo is a recipe for disaster. If it was a less powerful card like the GeForce Ti4200 AGP X8 then there would've been no problems but the FX5500 is a lot more powerful than that and can get fried very easily if abused. Sorry to say this, but the ****'s hit the fan.