Windows XP unable to boot

Hello,
yesterday, i was bit in rush so i could not wait for my system to shut down, thus i directly switched off from the power supply.
so today morning when i started the machine, it gave the comment as mentioned below

we apologize for inconvenience, but windows did not start successfully. A recent hardware or software change might have cause this.

If your computer stopped responding, restarted unexpectedly, or was automatically shut down to protect your files or folders, choose last known Good Configuration to revert to the most recent setting that worked.

If the previous startup attempt was interrupted due to power failure or because the power or reset button was pressed, or if you arent sure what caused the problem, choose start Windows Normally

now my problem is i have tried all the options like
1. starting from SAFE MODE
2 SAFE MODE WITH NETWORKING
3 SAFE MODE WITH COMMAND PROMPT
4. LAST KNOWN GOOD CONFIGURATION and
5. START WINDOWS NORMALLY.

but still i get this same screen displayed all the time,
somebody please help me out.
i am using windows XP pro, SP2