That box looks to have a very small power supply. Ask HP and ASUS if the power supply is big enough. My thought is it's power related.
I have an HP Compaq dc7800 Small Form Factor computer with a built in Intel Q35. I'm trying to install an ASUS EAH4350 SILENT graphics card. Without the card in, the computer boots up completely fine, running Windows Vista with 2gigs of ram. The ASUS card uses a PCI Express slot, but once the card's plugged in, and I power up the computer, it will beep 6 times in sequence with a red light flashing on the front, stop for a second, then start beeping again. The start up HP screen won't run either. Any idea on how to install it with it working? Any help would be greatly appreciated.