Hello. I'm having a problem with my Windows XP operating system. It SIMPLY won't start up. I recently returned home from a 5 day vacation only to REALIZE that my computer would not start up past a screen that gives me options to start up windows. However, none of these options work:
"Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt
Last Known GOOD Configuration (your most RECENT SETTINGS that worked)
Start Windows Normally"
Whenever I press enter on any of these, the computer simply freezes; nothing happens. My brother was using my computer while I was gone, and it turns out he shut down the computer by pressing the power button and it has not been able to start since. I would appreciate any help. Thank you.Here I post exactly what the screen says:

" We apologize for the inconvenience, but Windows did not start successfully. A recent hardware or software change might have caused this.

If your computer stopped responding, restarted unexpectedly, or was automatically shut down to protect your files and folders, choose Last Known Good Configuration to revert to the most recent settings that worked.

If a previous startup attempt was interrupted due to a power failure or because the Power or Reset button was pressed, or if you aren't sure what caused the problem, choose Start Windows Normally.

Safe Mode
Safe Mode with Networking
Safe Mode with Command Prompt

Last Known Good Configuration (your most recent settings that worked)
Start Windows Normally"

Once again, I'd appreciate any help. Thank you.