Applications keep on stopping to respond.

[ksenxx]

Hello, I have a macbook pro with Mac OS X 10.5.8 with a 2.26 Ghz Intel Core 2 Duo processor. Recently I've been having a problem with my computer when applications would randomly stop to respond for a few seconds, until after a while they wouldn't start again and I'd have to restart it. I don't know what to do, I'm a fairly new Apple user, so would appreciate if you could explain in as much detail as possible.
Thank you so much in advance!

 

[Gregg2]

What applications?
And that will tell us how many are running at once.
It could be that you're overtaxing your RAM.
How much RAM do you have?

 

[ksenxx]

Well, there's Safari, iTunes, Finder, VLC Player.. I usually run them together, but I've never had problems with this.

 

[SHADO]

Did you try repairing permissions with Disk Utility?