Pls help me

Hello,

my computer is stuck in a reboot loop. i have an intel pentium 4 desktop computer. it is windows xp home edition. the problem happened after i installed the windows service package 2 (i know, im a little behind). it seemed to install the update fine but after i restarted my computer i couldnt seem to get to my desktop. the computer manages to get to the light blue windows xp loading screen but instead of entering my desktop the computer reboots and the whole process starts over again. after reading other forums, i tried the F8 method but couldnt seem to make it work. last known configuration and safe mode dont seem to work but i may have not done them correctly; im no computer whiz. but after pressing the "disable automatic restart on system failure" option, i got this error message on the "blue screen of death" (this happened after the light blue xp loading screen instead of it restarting like it usually does):


what should i do? i dont want to have to reinstall windows xp and lose my data as i have some important documents and music mp3s on it. ive read about possibly doing a repair install? how does that work, would it work, and would it save my data? is there another option? thanks in advance.