Unity3D sometimes freezes my computer, when I look at a specific area in the game

When I am test-playing in the editor, Unity3D sometimes freezes my computer when I look at a specific area in the game. The models are not at all complicated, just office furniture, and I have tested by removing some of the more complex ones, but I still get the same random freeze.

I mean a total freeze, requiring reset, not a while-loop freeze. I lose mouse control, and ctrl-alt-del does nothing. These issues don't occur in any other program.

This freeze occurs once every 20-30 plays, with no code changes in-between, so surely I can rule out code?

When I look at the area that triggers the freeze, sometimes there is a lag before the freeze. On other plays, everything is smooth.

The errors did seem to start once I had updated to the latest Unity3D build.

If it helps, my setup is:

Unity 3.5.6f4,

Windows 7 x64 Professional,

DirectX11,

Motherboard: Asus Rampage IV Formula,

CPU: Intel Core i7-3930K,

GPU: XFX Radeon HD 7970 Black Edition,

RAM: G.Skill 8GB DDR3 1600Mhz RipjawsX

Any ideas? Thanks.