Apparently the only sure cure for this problem, if you don't want to lose any data, is to purchase a non-nVidia graphics adapter.
You could also purchase a new PC.
The problem seems to occur on older PCs with nVidia graphics. Changing either the PC or the graphics card seems to work in almost all cases. If you're on a laptop, changing the graphics is not usually an option, but none of the other suggested fixes seem to have worked, other that returning to a previous version of Windows and installing older graphics drivers.
The need to return to older drivers indicates to me that it's an nVidia problem.