Was able to bring the fan back to life by giving it a power wash with a dental waterpik filled with isopropyl and flushing out quite a bit of crude from the fan's hub. It is a bit noisy but it does change speed as heat builds... but the screen problems persist. The g750js will variously lockup on the welcome screen or a short time after login. Have two attached monitors which display as normal until the screen crash. When it locks up the verticle block pattern shown above is also seen on a secondary monitors. In safe mode the problem has yet to occur... so maybe corrupt video drivers? I've removed anti-virus software in case of conflicts and will start backing out updates. There are weekly restore points going back several months but any restore attempt always fails to complete. Ran SFC/scannow and the Win 10 system files check out. Suggestions are welcome. I've pulled screens apart in the past and will do that when all else fails but following navis995 comments the problem is not likely connections to the laptop screen itself as the other monitors are also effected. So driver corruption seem the best path to follow at the moment.

Did you ever repaste? Might be worth looking at your temps because even if the dead fan was part of it you might still be running hot.