I've never used to have problems with my graphics card and it's not overclocked or anything, I play games every now and then and so on. But now I had the weirdest thing happen in Celestia. After a while of zooming around in my experimental Vista install (with the latest official Forceware drivers), suddenly my monitor lost signal from the graphics card! Everything just went black, and monitor entered power saving! I couldn't do a thing and I'm not sure if the entire computer locked up. It didn't seem to be a BSOD error. (in that case I should've had an auto-reboot or a blue screen depending on system settings)
So then I thought the obvious thing "hmm, immature/bad Vista OpenGL drivers" and booted up my usually stable Windows XP install. And the same thing happened there too!
I'm using a stock Celestia 1.5.0 pre 2 install with only the New Horizons add-on applied, screen resolution 1680x1050, on a Leadtek WinFast Geforce 6600GT / 128 MB, P4 2.6 GHz and 1 GB RAM.
Hmm, this has never happened before, and now it has happened in two different operating systems with two different drivers! No idea what's going on, and it's the weirdest "crash" I've seen in quite a while. I'm not sure how an app can even cause this, especially as my graphics card is clearly not overheating (no problems in far more demanding applications than Celestia). So I'm still sceptical it's Celestia, but perhaps it's some sort of Forceware bug.
I may try Celestia 1.4 next to see if it solves my problem. I can't recall any problems with that one in the past anyway, and I've used it quite a bit.
Just posting in case anyone here has had something like this happened.
Edit: Driver numbers are ForceWare 97.46 for Vista x86 and 84.21 for XP respectively and the complete system crashes (??) seemed to happen after a few (like 3-5 or so) minutes of Celestia use.