My 'rents XP box downstairs that had started to BSOD more than it did before, do you know who I blame?
D-Link.
The only change I did was to add in a cheap-o wireless card from D-Link, with shitty, unsigned, drivers.
the box was rock solid, and up-to-date, after I added the card it was less stable, BSODing once every two weeks.
I un-installed the driver, removed the card. Re-installed the driver and put the card back in.
It was fine.
for some reason, D-link made their drivers so you had to install them first, then physically install the card. Incredibly stupid on D-Link's part, if you ask me.
I just installed service pack 2 on it, run great!