Nvidia 740M intermittently not working

I have been having an interesting issue with my Geforce GT 740m for the past few months. The card will work fine, then after playing a game or watching movies for a few hours (things that use the dedicated graphics over the intel integrated), the game will crash and I'll get a driver error in the taskbar. Sometimes this is followed by a BSOD. After this point, the card seems to disappear, it can not be used, detected by any software including Nvidia's software or GPU-z, and becomes hidden in device manager.

Once it has done this, it's completely random as to when it reappears, could be hours, days. What usually happens is after hibernating, when I turn the laptop back on, rather than restoring the laptop will startup as if from being shut down, then I check and the GPU is back. Whilst it's working, I notice no tearing or performance issues.

I suspect there's a fault with the card itself, though am hoping someone may have some sort of solution. I have tried updating/restoring drivers, system restores and have reinstalled windows, but to no real avail. Unfortunately this started happening just out of warranty (probably only a few weeks out, typical!), so I'm hoping someone may have some ideas.

Thanks in advance.

I'd be happy to provide any more info that may be of help.