Thanks for the answer. The PC has 4gb of memory because I upgrade.Your textures might be too big. If there's nothing you can do, you need to upgrade your memory of your computer. How much do you have? Anything under 2 gbs, you're going to have problems.
100 textures. 50 to diffuse and 50 to bump.How many 2k textures do you have, and how many polys are in your scene? It just sounds like you have too much stuff in your scene, and your computer just can't handle it. I remember working on a shot at work, and I was easily maxing out 16 GB's of ram.