Ok I have searched for hours on this with no luck yet. I am a pc technician and I have a customer's pc in here that was stuck in a boot loop. After disabling the automatic restart on failure so I could see the error message, it turned out to be the c000021a fatal stop message. I have researched that error up and down but nothing relates to my situation. I tested the RAM and the hard drive, they are fine. I did a chkdsk.. no help. I decided to go ahead and do a repair install, well it never makes it through it, it just keeps rebooting, saying Setup is being restarted.................. and reboots again. I'm screwed at this point because I cannot get into safe mode since it just tells me that setup cannot continue in safe mode. I have tried all the options on the F8 screen. I tried doing a fixmbr and a bootcfg /rebuild just for the hell of it..nothing is working. I really dont want to have to tell the customer that they need to reinstall. Not that its a huge deal but as anyone knows, its a royal pain in the *** to backup files (on your own pc, much less anyone else's where there's the fear of forgetting something). Is there a way to manually cancel to the stupid XP setup? I have tried some suggestions but mainly I'm told to look on the OS choices menu off the F8 screen, but there is NO cancel XP setup option. I know you can access system restore from a command prompt, maybe going to a day earlier would fix this, but the only command prompt I can get to is in the Recovery console and it wont let me run the program from in there. I tried a 98 startup disk and was told the program couldnt be run from ms-dos mode. Can someone please give me any other suggestions before I am forced to wipe it out and start over? It all seems to be related (I think) to the winlogon process. I'm guessing it got screwed up but not sure how since the customer brought it in that way. All the suggestions on MS website point to different causes..ones I'm sure won't help me.