About a month a go when my computer would start up, and the screen would be blank after the hp screen would come up, i would hit f1 on the blank screen to start the windows xp screen where it took about 5 minutes then finally loaded.. about 3 weeks ago after i started my compiter, i got a message after i hit f1 that said my windows\system32\config was corrput or missing.. so it wouldnt boot up, after about a week i started it back up and i got a message saying my windows/system32/ drivers/ isapnp.sys was missing or corrupt. so i put in my xp cd to try and repair it from the recovery console.. and i cant do anythign cause access is denied whenever i try and do anything.. and it doesnt ask me for an admin password.. so idk how i can repair it.. i then tryed to boot my computer up today.. and it didnt say anything was corrupt or missing, after i hit f1 on the blank screen, it would go to a choice of whether to boot normal, boot from last know good configuration, or boot in safemode, i tryed all the selections.. and it just shows the windoes xp screen, then restarts, and its a never ending process .. it just restarts. is there anyway to repair this problem, or do i have to format it and start from scratch?? any advice would be appreciated