Getting random crashes - graphics card fault?

[badger]

AMD FX-55
WD Raptor 74GB
XFX 7800GTX
Creative X-Fi Fatality

Over the past few days I've been experiencing random crashed on my system, always after playing games for a while. The other day I booted up and had no display - the screen was blank. I popped the case and wiggled my graphics card and that seemed to fix it.
Is my graphics card on its way out? It seems the most likely suspect but I'm really not keen on buying a new one - I hadn't planned on an upgrade until DX10. Could it be anything else? I have noticed that the card is at a rather funny angle in its slot, I've got a Lian Li V1000 case so the card is at the top of the case where the PSU usually goes. Maybe try taking the card out and find some way to prop it up?

If I do end up having to replace it though, what's an affordable Nvidia model with similar or better performance than a 7800GTX?

[notsobig]

Strip everything out and re-align your mobo to your case holes properly? Sorry can't think of anything other than that.

[harry1]

clear the cmos, check the seating of the card take it out then put it back in.