HDD problem

Last night I installed msn onto this PC (which I've had for nearly a month now) and it wouldn't work, so I gave up with it. Played a few 3v3's afterwards, and near the end of the last one my PC rebooted (blue flash on the screen and then some multicoloured specs for half a second before reboot [not actual "BlueScreen"]).

I went back on ET and finished the game and went to bed. When I got back home today and went on my PC I instantly uninstalled msn as I saw it and went on ET to go to u|k serv, when I got kicked by some PB problem - said something like "couldnt load PnkBstrB.exe" aswell as "server handshake failed" at the bottom (no clue what that meant). I tried reconnecting and I was kicked again with the same reason.

I rebooted and opened ET, it said there was no such program as "Enemy Territory" so I went to My Computer to try to access the Local Disk (Z:) Drive and it came up with: "The disk in drive Z is not formatted; do you want to format it now ?"

I already formatted it a when I first got this PC (a few weeks ago) and I have alot of fles on it, not important things, just demos etc (which I don't mind losing) but I would very much rather it being fixed tbh, instead of formatting it.

Thanks if you try to help ;)

EDIT: It's a Samsung Spinpoint 1tb if that helps.