Help i just reinstalled win xp and the am locked out of the my backup folder

help like i said in the title i just reinstalled windows xp with a my backup folder saving all my files the thing is though i had my account marked private so my little brother would be locked out of all my stuff and now when i try to get into it it says access denied

You will need to regain ownership of the folder. You will need to disable Basic File sharing, then right click the folder you want to take ownership of. Then select sharing & security, and click the security tab. Then, click on advanced and owner, and claim it.

If it still says you can't gain ownership, reboot into safe mode and log in as Admistrator, for only He may gain all ownership over His feifdom

Here is how you disable simple file sharing.