WINDOWS XP BOOT ERROR PLEASE HELP

[ericiscool]

My brothers are running a windows XP sp2 Dell, and somehow after i reformat it they seem to mess it up everytime. they finally hit an error i havnt seen before and im wondering how they managed to get it. When the compter starts it goes to a windows NT looking enterface and says only administrator or eric can login (im eric) and i know i never set a password for admin or myself, so i hit enter, and it acts like its about to go to desktop, when suddenly outta no where a explorer.exe application error pops up and says "the application failed to initialize prperly (00c0000005). click on ok to terminate application." so i click ok and it goes to a blank screen and the start bar and or desktop never loads. anyone knwo what may be causing this?