Patch Tool Not Working

Using Windows XP
Using Photoshop CS2

I lasso the area I want out of the picture with the patch tool, click on the inside of the selected area and drag it to an area that I want cloned and when I release the mouse button and nothing happens. I looks like a small about of change has happened but not much. It is almost like there is an opacity option set to about 10 percent for the patch tool. Please help, is there something that I need to change?

The patch tool was working for months up to this point.

This has happened to me a couple of times and learned on this site that resetting the preferences cures the problem every time. I have to re-validate some of my plug ins, but not a big problem.
Cec

You could try just resetting the Tool.