some photoshop tools are not working :(

Hello fellow lj-ers.
I recently realized that I have many problems with my Photoshop CS2 Program.
I'm thinking of reinstalling but before losing all hope I thought I'd try here.

The dodge tool , burn tool , blur tool, stamp tool and all many others like that don't seem to be working at all.
I tried googling it and even asking some people I know about it.
I tried the blur filters to see if they would work and I got the same result.

I'm so totally lost.
I don't even know how this could've happened.

I can't live without these tools :(
HELP?

thanks in advance.

P.S: Yes I did try to look under the memories for "Photoshop - Problems and Errors" and didn't find anything relevant to my problem.
and Of course I'm not trying those tools on an empty layer.

EDIT> I actually reinstalled Photoshop. It works now.