Fullilove

Man do i ever have a big mess on my hands. So here goes... While i was away at school my brother decided he was gonna take an old XP laptop of mine (Compaq R3000) and "upgrade" the os with a Dell Vista Installation disk. Doh! Of course it didnt work, and now i cant do anything with the machine. Im sure he didn’t even think about the contents of my harddrive so its probably wiped When you boot up the machine it goes to the windows loading screen and then after a second it goes to the next where it displays an error. It reads "The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. Press OK to restart the computer." Now restarting the pc just brings you back to this. All attempts to repair using the installation disk didnt work. I had thought about using this pc just for storage since its an old machine (about 6 years now) but now i cant do anything with it. Is it possible to remove the os without being able to boot windows, and possibly save my hd content?? Please help! Thanks