Disappearing files

I rarely turn off my MacBook but I did last night. When I turned it on this morning, my dock was reset to the original size and my desktop picture was changed back to default. Also, my documents weren't in their usual folder - they didn't completely disappear, thank G-d, but were under Users in Macintosh HD.

My computer has been acting pretty funny lately. A few weeks ago, I woke up and iTunes was completely reset and all of my songs were gone (on the computer, but not in iTunes)

I was fiddling around with the keychains a few weeks ago because I was having trouble connecting to the iTunes store - I don't remember what I did - but could that have something to do with it?

maybe it could be a software problem

I get the same things with my macbook sometimes, things go missing and its forever freezing on me. Maybe if you use disk utility to see if your system finds anything that it can repair.

You changed your user or home folder name. That is a no-no unless done properly.

Recover from renaming your home folder

Mac OS X 10.3, 10.4 or later: Return to default desktop, apparent "loss" of home directory
Mac OS X: How to change user short name or home directory name

This is probably not the issue with iTunes of a few weeks ago and may be too late for troubleshooting that issue.