Cannot cancel a render

Hi,
Over the last week I've not been able to complete renders or cancel them. They seem to hang at the 3 to 30 min mark and freeze my computer. It's not a too much in the scene problem as I'm not using anything complex don't have other programs open etc. I can't hit cancel I can't, task manager, I get no error msg. The render just hangs for hours and nothing happens. I have to force shut off my computer. Thoughts or ideas?
Comments
Sounds like a driver or hardware issue.