can’t boot at all stop c000021a status of 0×000003a

HELP PLEASE!! PC running XP, was installing service pack 3 was taking forever:( I had to leave…I made the terrible mistake of turning the PC off with the power button while it was installing sp3, I thought it had stalled. When I turned it back on it went to a black screen that said something about windows was not shut down properly, down at the bottom it had start in safe mode, last known good configuration and start windows normally all the choices just made it restart and go to the same black screen.

I googled the problem and followed the instructions for booting from the recovery console and entering the command for uninstalling the service pack…it just started listing 1 file(s) copied over and over again. Tried hitting esc and control alt delete but the only way I could get out of it was to shut the pc off by the power button.

I disabled restart on errors and rebooted, it then had a blue screen that said something about autocheck not found and I think autocheck skipped, the got the BSOD that said:

STOP: c000021a (Fatal system error)
the session manager initialization system process terminated unexpectedly with a status of 0xc000003a (0×00000000 0×00000000)
the system has been shut down:(

I am in a state of panic…could never afford to repllace this pc and have lost the XP cd. I can boot from the recovery console…is there anything I can do to fix this disaster?

Thank you in advace for your help,

Greta