P6 is a major memory hog. It might help if you reboot windows before you run it. A lot of other programs are memory grabbers, and even after you close them down they still hold on to the memory. I have like 316 mb of memory, and even I have trouble using Pshop now and then if I don't start with a fresh memory file. Also, you might see if you have enough room on your scratch disc. Photoshop doesn't just save an image, it also saves a memory image of your work, usually on the scratch file. This is what allows it to use the history brush and undoes and all. If your scratch disc doesn't have enough space on it, app 2 times the amount of your memory, that can cause problems too.

Talent is God's gift to you. Using it is your gift to God.