External HD empty after 360 connection

ok, this is basically the run down, i havent looked around this forum because i'm pulling my hair out lookin through google for ANY help at all, and i'm at a loss here.

right. my computer is protected from habit (albeit just 1 tap on the space bar), but today, it wouldnt let me type into the password bar in the vista opening screen. thinking it was the batteries i changed them, no joy. tried it on a laptop= worked. computer = no. tried a different keyboard, still no joy (my mouse was still working, it was an Acer mouse+keyboard wireless set), so i was rather confused. thinking it was a virus, and also thinking it was time i formatted my computer anyways i reinstalled windows XP, after unplugging my HD and plugging it into my xbox

whilst trying to find out how to get my music onto my xbox so i wasnt bored out of my skull, i noticed i could use it as a memory card, so to speak, for my save games which would be handy as a 2nd xbox will be coming into the house. this took up 16gb i think.

now i couldnt figure out how to actually get my music on there so i dealt with what was there already.

then after reinstalling XP, i plugged my external HD back in, and it's all gone. pictures from my 21st in amsterdam, new years eve in amsterdam, so many pictures and songs and tidbits i'll never be able to get back again, unless the hard drive can be rolled back or something.

PLEASE, someone give me some good news.....