I'm an idiot!

what have I done?!

I was on my school-laptop, and I saw that my network ID was like sssidfs324sass something, so I thought I would change it, and now I can’t log in on it! Is there anything you can do, like reset the computer name or somoething, or should I just get the tech guys at my school to ghost it for me? I’m really pissed at myself right now, because I have a test coming up tomorrow, and the files are on my computer!

I managed to get into the computer on my win2k (I use it in my LAN class), but I can’t get it to see my external HD, so I can’t make a backup! ;(