CROCKERD

ok i got this problem too,for some reason i have two choices for OS,WINDOWS XP PRO AND WINDOWS xp PRO SETUP, IF I ENTER JUST WINDOWS XP pro i get the, system32\config\SYSTEM is missing or corrupt error, if i enter the setup selection, i cant do anything but quit? i got windows XP CD but i dont think it is the original, so when i enter windows xp setup it says something like, cannot find where windows is installing from, and all i can do is press F3 TO QUIT??? please help me, i have over 4 thousand songs on that hard drive plus my own music i have made for my university corse, i really cannot afford to lose it, would appreciate any help.