A couple days ago I turned my Lenovo ThinkPad laptop off after it being on all night. Left off maybe 5-10 minutes & booted back up, all was fine at first then it looked like the screen had been shattered (it wasn't) but it appeared to be shaking. I powered off & let it sit a bit, removed battery & pushed power on button for about 30 seconds. Plugged it back in with out battery & all seemed fine for many many hours till some time this morning when I heard a strange hum, saw screen like the first time, powered off again. Hours later I booted it up, it is again running ok, I checked Device Manager & NO Exclamation marks ANY where. I do have an extra monitor I can hook up but I fear the video card might be going out????