Do not install Vista.
It has bad bugs.
I was thinking of formatting my main HD (it was slow) and tried the Vista Beta. It has good features, but besides;
It's unorganized. You hvae to search for years to find a simple option menu. They changed everything, and that's much worse than XP. Control Panel just "sucks". I was unable to find an option to turn off ClearType, which I hate, and which Vista uses not only on IE, on almost all over the interface.
My mouse cursor icon gone crazy using Vista, there are lots of compatibility issues as it's just a beta (even though I downloaded the latest beta driver for my nVIDIA geForceFX 5700 from nVIDIA's site for Vista.)
Final decision: Just wait for the official release.
I have to admit, I reckon Vista is actually slower than my full blown KDE interface. It's a total waste of RAM and CPU cycles... I mean, it's a PC. Who gives a crap if you can rotate windows or see through stuff.
Personally, if your PC is being problematic, I think going to vista would make it ten times worse. My advice would be to reinstall windows XP and if that doesn't work run a hardware scan of some description (memtest86 is a good place to start).
Besides, you can't get a legal copy of Vista atm anyway, can you?
Meh, when Vista comes out I suggest getting a new PC. I mean alot of my hardware is probably outdated now, and it gives a chance to have a fresh start on a pc.
Then again, when vista comes out I will be on XP for many more months.