please help graphics card nightmare HD2600XT crashes

Please help upgrade my Radeon X600 graphics card. I have a dell dimension E510 with Windows XP Media center edition all updates have been installed. Computer is an Intel Pentium 4 CPU with 3.00GHz with 4GB RAM. I have a PCI-e slot. Recently put in an Antec Basiq 500 W power supply http://www.antec.com/us/productDet [...] dID=23500. I cannot figure out why the HD 2600 XT won't work, If i disable VPU it last about 10 minutes before crashing and VPU is enabled takes well about the time for windows to start up. Please help i'm soooooooo fed up trying to get anything decent to work. I'd like to spend around $200 or less. I've also tried a Radeon X1550 XFG which i found to be well total crap, but it did run. maybe i'm just stuck with the X600. Now i'm looking at a Geforce 8500 or 8600 series. Help please want this working fast so my head isn't constantly spinning with why won't things work. About to just go buy a bunch of cards and return everything that doesn't work.

Just a thought but i don't think it matters.. My X600 is a DDR1 card since all cards seem to be downwards compatible it shouldn't matter if the card is a DDR2 or GDDR3.

I uninstalled everything before putting in the new card, and with VPU enabled the monitor shut off, sometimes before windows xp could even load, never lasted long enough to try a game. when i disabled the VPU i could get windows loaded, and started sims 2 and crashed to a blue screen saying it was bad drivers or hardware. after 3 tries with different driver versions, i gave up returned the card and got a geforce 8600GT which is running fine. most likely it's just crappy ATI drivers, I know my old X600 if i put the brand new drivers on, i got all sorts of weird problems. Not sure i'll ever go back to an ATI product again, at least till they get their driver issues sorted out.

VPU is on the catalyst controller suppost to keep it from crashing if it encounters an error, but for some reason it was causing more frequent crashes. VPU should recover things without a total crash but well it wasn't recovering at all. video cards should be that easy to install, i know all i did was plug in the 8600GT and installed drivers and it's worked fine.