I have a HP compac dc7700p tried to upgrade to dual monitor with G force 210 512MB DDR3 card
Would not work beyond windows xp boot screen, suspected PSU to small so changed to Corsair 500W with 32amp +12V still no joy, but is working fine with an older card (RADEON X700 PRO) but fan on this is noisy, could the motherboard be the problem ?
If the motherboard is PCIe rev 1, and the video card is 2.1, could be a compatability issue. You can try a bios flash. A 210 does not have a lot of power requirements, don't think you needed a new power supply, although it can't hurt.