I have a T410 with the NVIDIA Optimus option. I normally use the integrated card only and occasionally I do something with the discrete one. The BIOS setting is set to "Optimus". Yesterday, I noticed that I could not use the discrete graphics. When checking the device list the NVIDIA card was not showing at all. I rebooted once, checking the BIOS setting, which was still set to "Optimus" and it still didn't show up.
I tried setting it to "Discrete" and then after rebooting the laptop would just shut down after a few seconds without any error message showing on the screen or any beeps. I tried starting up a few times and every time it would shut down after a few seconds. At that point I noticed that it was getting very hot in the few seconds that it was up before it shut down, so I'm guessing the reason it is shutting down has to do with overheating. I tried a few more times to power it up and go into the BIOS to switch the graphics mode back but it would always shut down before I could do that. Sometimes I would almost get it but it would shut down just before I save the BIOS settings. Very frustrating.
Then I unplugged it, removed the battery and left it for an hour or so. Then, I plugged it back but without putting the battery in at first, and this time I managed to change back the graphics setting to Optimus and now, with the integrated graphics it works fine and the NVIDIA card still doesn't show up. Except for that it seems to be fine (with the battery back in) and it is not overheating and the fan works fine.
Is this a known problem? Has my NVIDIA card died?