Hello aplogies if this may be in the wrong section.

Anyway, for some reason the airbrush tool won't work for me. It was working fine until two days ago. I don't think it's my tablet's problem because the effect doesn't show up at all in the brush presets window, wether I select the airbrush option or not.

I was using Photoshop 7.0 and considered reinstalling but I installed the CS3 version instead, hoping it would work. But it doesn't. I reloaded the application and restarted my computer as well. Nothing worked

Is there anyone who can help me?

Thanks, all replies appreciated.