Being geeky, I have a few running computers, but only one that's fairly "modern".* Which I hosed last Tuesday trying to shrink a partition so that I could add Windows 7 Ultimate for a dual boot. Everything was backed up two days prior, so I didn't lose too much, but still, it required reloading the OS completely.
*The one I'm on right now is one of the older ones that I'm updating, increasing RAM and upgrading the video card. It could run Windows 7 at any level right now, but I want it to howl as loud as it's capable, I can put another gig of RAM and put a much better video card in it. It's 6 years old, but it was a high end motherboard when I got it, even if it's only 32 bit.