Blender Crashes During Unwrapping

I’m using Windows Vista 64 bit Home Premium, Gateway FX6800-01e, Intel Core i7 and I’m using Service pack 1.

But if I have a split screen, I select the vertices and I unwrap and Blender closes. I unwrap in single screen mode, and when I switch to the UV map, Blender closes.

Please help. I’m excited and wanting to learn, but can’t complete projects I’m wanting to do if I cannot unwrap.

Is there something else I need to download such as a patch to assist with this problem? I’ve downloaded the correct version of Python which is 2.5.4 I believe.