stuck at 0 percent lighting build

Just stops at 0 or 20 percent. All worked yesterday, on a map im making now nothinv loads. It doesnt break or have an error just stops. Im not sure what to do i even tried uninstalling everything and reinstalling again hoping that would just fix it back to how it was but still its carried its problem over.
Just sat on 0 percent, im using the bog standard, as it loads, fps startings map, click build and its doesnt seem to get past that.

I would blame my pc or map but it was all working fine, if not slow, and now just nothing. Very sad

Can you tell the computer specs?(bit, Ghz, OS, ect.)