Currently have Geforce 4600 card and tried replacing it last night with Radeon 9800 pro card. The computer would not boot. It just hung at the windows XP screen, when I reset computer didn't come back on at all! I know the card is fine as it's from a brand new pc that works fine. What would be the reason for this with this card?

Ok do this: Put back in the GeForce 4600 Card and boot up the machine. Does this boot into XP? You should have done this, if not.. UNINSTALL the Nvidia drivers for the GeForce card. Reboot it as asked and when it loads up it should be in a screwy resolution etc showing that there isnt any drivers. Then run the Radeon setup CD and install the Radeon drivers (and 8x agp option if your board supports it) When it asks to restart, say no then shut down the computer. Install the Radeon 9800 and it should boot up fine. If you had not done this then you must not have read the instructions for your video card. If you have done this and still no luck, Then try the card on another computer to ensure it is ok. If it is then your windows is probably messed up somewhere.

ATI is very insistant that you remove your old video drivers B/4 updating the drivers for their video cards ! I would imagine this applies to other video drivers also, when installing an ATI product ? Good Luck,Nick

well as an update to this i've managed to blow my monitor! I uninstalled the existing nvidia drivers, then rebooted. I downloaded the latest radeon drivers but when i tried to install it said couldn't detect appropriate video card. So switched off, swapped to radeon card and tried booting several times into safe mode but wouldn't get that far. Next thing is my monitor blew and having to get a new one! What am I doing wrong?