Since posting this, I've actually received an e-mail or two saying that there appears to be another issue relating to NVidia drivers and 4-bit colour that some people are evidently looking for answers to. Whilst I don't have an answer for this one, if someone wants to reply to this or e-mail me via my username @ arloria.net, I'd be more than happy to have the additional information here.
Other than that, all I can give you guys is speculation - It's probable that there's a similar root cause - The card or monitor isn't being detected properly, for whatever reason, thus resulting in a safe default that nobody wants to use. As to why, of course, is what you guys want to find out. Until I receive more information (I admit to not updating my drivers since this problem) on what causes it, I can't put the answer here for you. Sorry.:)
Other than that, all I can give you guys is speculation - It's probable that there's a similar root cause - The card or monitor isn't being detected properly, for whatever reason, thus resulting in a safe default that nobody wants to use. As to why, of course, is what you guys want to find out. Until I receive more information (I admit to not updating my drivers since this problem) on what causes it, I can't put the answer here for you. Sorry.
Lulolwen is a sniffle-causer
Last night I had to rebuild my PC after a series of stupid errors that combined and left me without an OS, I ended up installing XP but ran into a problem where the card (An NVidia 7600 GT) would be detected, but the screen resolution and colour depth were stuck at low settings, 4 bit colour and 800x600 screen resolution, possibly 640x480. I use a widescreen monitor, a Fujitsu Siemens 23" monitor of some kind, which may be partially to blame. The results were independent of which NVidia drivers I chose to use, and my system returned to a semi-normal state when the drivers were uninstalled, making it look like a driver problem.
It turns out that the problem appears to have been my version of Windows XP - I was using Windows XP Service Pack 1. I upgraded to Service Pack 3, though Service Pack 2 would no doubt have fixed it. I'm not sure what it is about it, but I have a few equally-implausible theories.
It might have been that the drivers require some kind of call that changed between Service Pack 1 and Service Pack 2. If this is the case, it's a wonder that the kernel didn't roll over and die. So this is implausible, but still possible.
It could be that I simply had some unique corruption that updating managed to fix, this seems implausible for the same reason - It's a wonder the kernel didn't panic if this were true.
So more likely is the simple explanation - There's a lack of support for widescreen monitors, or at least my monitor, in Windows XP. Perhaps updating either gave XP the knowledge of what to do with my screen depth, or taught it how to detect the modes it's capable of. It still identifies as "Plug and Play Monitor", but at least it's back to doing 1650x1050 now.