Invisible Cursor!

Hey hey,

I have a question:
Sometimes when I'm working with Photoshop CS2 all of the sudden my cursor disappears! (This can occur with brushtool, ellipse tool, etc)

Well.. It's not totally gone; It's just invisible above the window I'm working in. When I put it on my toolbar for example it's there. And when I want to put it above my canvas it disappears again. When I try to draw something anyway, it gives some sort of very thin line which kind of shows what I'm doing, but as soon as I release the mouse button it all disappears again. Closing/opening Photoshop or rebooting the computer don't help.

Can anyone help me?

because you using some tools thats why..