Photoshop is a ram hungry beast. I have never had it run right with less than 512mgs of ram. Or you have to work on real tiny picturea. Also you have to make sure your scratch files are set right. If all you have is one hard drive then you have to set C as you scratch. I run a second hard drive, 80gig, partitioned in to three drives. So scratch is set to the three partitions first and the 4th scratch goes to C drive. By the way I use 6.5 most of the time..I hate vers 7....so there may be some idiosyncrasy in 7 I am not aware of. I would go to Adobes site and check with their forums. They are also very helpful.