Computer update: we took it to a computer shop this morning and it's apparently the PSU and the motherboard that went. Processor's fine, vidcard is fine, HD is hopefully fine. Since it's still under warranty, we are sending it back to the place we got it from, and they'll replace the fried components and then send it back. I managed to get my CD out of the drive - thank [insert deity of your choice here] for safety holes and long paperclips - but not to get my data off the HD. The drive is so large and our other computers so old that the BIOS won't recognize such a large HD, even if it's hooked up to it. (Yes, we tried.) So the computer is getting sent back with a large sheet of paper reading "please don't format this HD, important data on it" taped to it. If they format it anyway, I'm gonna murder them one by one. :P
Got my NaNoWriMo story back though, thanks to those who sent it to me. At least now I know I haven't lost everything. :)