Serious Photoshp Elements Problem, I need help! Elements keeps crashing my computer! Options

[Venia]

I've been having problems with Elements 4.0 on my Macbook. When I got the program six months ago, it worked great. In the past few months, however, it's been freezing up, timing out, unexpectedly quitting (in which case I lose up to 20 mins of work), and even crashing my whole computer. Just the other day, it somehow deleted all of my brushes, probably a good few thousand. It will take me all day just to reinstall them.

Will reinstalling the program help? I tried deleting it, emptying my trash bin, and reinstalling it, but that didn't seem to help. Maybe it didn't actually get reinstalled? I'm kind of new to Apple computers, so I don't know if there's anything special I need to do to uninstall and reinstall a program. Can anyone help me? I'm really frustrated with this problem right now!

[superficial]

Sometimes it's a problem with the local disk that you save the program on. How much space is left in the local disk that you saved your photoshop on? If there is a very little, I suggest that you uninstall some stuff in the same drive.

Also, did you already use a Macbook when you first had elements? (when it worked fine)