A driver error would tend to suggest driver, but that's if it's the same one. There's other tips about the blank screen in lw such as turning 3D rendering off or something to that effect. But that might not apply to your card. (Sorry things are happening very slowly on my comp at present.)

If there's no BSD then it might also be a heating issue.

How long have you been using LW & how when did this problem start? Was it after a LW update or ... ?