Is this the same computer you do your Illistrator and Photoshop workings in?

Or has it just recently just started doing all this freezing in PS.

Did you download any suspecious content recently?

Edit/
I got 2x 512 DDR Sticks when I built my box back a few months ago, I believe the RAM ran me about 199.00 for premium quality sticks.

What kind of computer do you have and how old is it? It might be worth it to buy a brand new computer rather than upgrade, which is true in many searios and cases.