I have Windows XP, 60GB HDD. I wasn't doing anything out of the ordinary, just left the room, and came back in to a rebooted computer, at a screen wanting me to insert my system disk. Well, I've tried a number of things, and all end up at the same thing. I end up with an error window saying in the menu bar "lsass.exe unable to locate component" and message box saying "this application has failed to start because" and then nothing else except the ok button. I have tried safe mode, repair console, debugging mode, setup, and even tried copying the file from the system disk to the system32 file. I've also run across something else while trying to get around this. Don't know if it's because of the many ways I've tried to get around it. Along with this lsass.exe window that pops up, it's continuosly trying to start setup. I try safe mode, and it says that "setup cannot run in safe mode", and the lsass window, and when I try to start normally, it gives me a screen saying that setup is restarting, then goes to the Windows installing screen, and it has 39 minutes left, and pops up the lsass window, and doesn't do anything more. No matter what I do, I have the lsass.exe window, and setup trying to run. Does anyone have any suggestions other than formating, to fix this problem? I have searched the forum, and the internet, and have found nothing more besides that one suggestion. I've repaired my comp several times without formating, when sometimes I've been told that's all I could do, so I won't give up easily! I'm really beginning to hate Windows XP! It has a mind of it's own! Thank you for taking the time to help me. Any suggestions are very much appreciated!