So my new graphics card arrived today Browsing at 640X480 - best GFX for a Asus P5K board... - wasted no time ripping out my old Geforce 8800 GTS 640MB and replacing it with the budget alternative, the HD4850 512MB.
Plugged it in, checked the seating, checked the cables, connected the kettle cord, flicked the switch on the PSU. (wait, was that a slight pop I heard?) Motherboard green light. Check. No GFX warning red light. Check.
Press the power button. Nothing.
Crap.
Take out the HD4850 512MB, put the 8800GTS back in. Cables. Lights. Power button. Nothing.
Crap.
Lights are on so the PSU is fine. Would also indicate the MB is okay, although it's possible the PCI-E slot blew. I'm left with the GFX, but I'm willing to discount as the 8800GTS should have worked once re-inserted or the CPU.
Anyone care to offer an educated guess?