Harry, I'm afraid it is time to upgrade your computer.

As has been said above 4GB of RAM is not nearly enough for image processing. What OS are you using? When I built my last computer I was running W7 with 8GB of RAM and had constant screen freezes. Added another 8GB and haven't had a problem since.

If you are at all handy with a screwdriver it's not a major job to install a new motherboard and RAM. Your CPU and other hardware should be up to the job although you may need to upgrade the GPU.

If you can afford it the CC Lightroom/CS6 combo is what I use at $13.20 per month although you can do about 95% of your processing with Lightroom. Photoshop adds layers, masks and filters etc.

If you need assistance with hardware for an upgrade just yell out. There are some pretty tech savvy members here who are more than happy to assist.