That's a sign the OS has sustained a fatal blow.
You can google the following for ideas.
1. XP REPAIR INSTALL.
2. XP PARALLEL INSTALL
I am having problems booting into Safe Mode. I am running Windows XP (SP3) and it is kept fully updated. I have no trouble booting normally. I can get to all the options by pressing F8 and can select Safe Mode from the list. It starts to boot but freezes when it gets to Bdisk.sys After a few seconds it boots into Safe Mode but crashes when I try to login with either my own login or Administrator. I can't select Disable Automatic retart either so I can't get a BSOD to see ant error message. I have completed a repair install but that hasn't helped. I have run CHKDSK and Fixboot from the Recovery Console but that hasn't helped either. Not sure what else to try now and don't really want to do a complete re-install.
Can anyone help?