MacBook mysteriously restored itself! Questions

[laughingbabe16]

Last night, I did my scheduled backup of my macbook, and changed some preferences in itunes, so that I could also backup my music library on a cd. Afterwards, I restarted my computer (seemed to be lagging a bit) and then after i put in my user name and password, the whole computer restored itself back to factory settings, however, my school documents and installed programs were still there. I couldn't find my music or photos. However, thank god for backing up my files every night or I could have been S.O.L

My question is: why did this happen? How can I prevent this thing from happening again?

Also: I just checked the amount of free space on my macbook, and I only have 28,27 GB of space free. What files can I delete on my computer that I wouldn't miss? Also, can I move my iPhoto library to my flash drive to save space?

 

[dartzorichalcos]

Did you change anything in the home directory? If so, you should check something like this.

 

[laughingbabe16]

I did. I added a space in between my first and last name, and yeah.. didn't think a little thing like that would cause such a problem.

Thanks!

Any ideas on my second question?

 

[dartzorichalcos]

Any ideas on my second question?

I don't know about the flash drive question because I never used a flash drive before.
For deleting programs, delete GarageBand if you are not using it, disable Dashboard because Dashboard can be a memory hog, delete iDVD if you don't plan to burn movies to DVD.
For more information, check this guide.