Hi, im back.. again.

This time, my older brother had made 2 user accounts for this computer (idk why).. and when he told me, he said that all the files were lost so then i went to check it out, and my first thought was to try and do the system restore point... but that didnt work since it says that i dont have sufficient security privileges to restore my system, and that i either need to contact my administrator, or log out then in again as an administrator and try again.
After that.. i tried doing "Last Known Good Configuration" and nothing really happened except for the fact that it went to the 2 users that my bro made..

anyways, i'd like to know if there's any possible way i can gain back my lost files.. please and thanks.

Restart your computer. On startup tap F8. You will enter a selective startup menu, select Safe Mode and continue. At login you should see an Administrator account. Login as the Administrator (Note: If it has a password it is most likely your password). Now you should have Administrator rights so try to do a System Restore from there.

Hope this helps,
Austin