I have a Lenovo thinkpad T500 with an HD3650 graphics card.
I use it on my docking station through a dvi to hdmi lead to my tv.
After around 40 minutes the screen on both laptop and tv goes white or grey. If I shutdown and restart it then seems to runs for hours without problems so I've been reluctant to blame anything overheating. It freezes and does not allow me to try anything other than a forced restart.
Nothing seems to come up on the log to help either!
Your thoughts would be welcome please?
Try replacing the cable, try using compressed air to clean out the connection ports (carefully.) Try cleaning out the dust inside the laptop using compressed air.
I agree, doesnt seem like overheating if you can restart and keep at it for hours. Unless variables change, for instance the laptop is on a flat surface no, whereas before you were using it on a bed blocking the ports.
Lots of different things go into it, I hope its nothing major. Some internet research suggest bad LCD screen cables, that could be fixed as easily as reconnecting them properly, or replacing them. It could be as bad as a motherboard going out, or LCD screen.
is the laptop under warranty? Can you purchase an extended warranty? This type of issue is quite expensive to diagnose and repair, and there is only so much we can do. I do love thinkpads though. My x201s is running strong after 4 years of faithful service.