Why does my laptop GPU cause BSODs, but sometimes works fine?

I'm having issues with my old Alienware 17 R1 and its Nvidia 770M GPU. My computer often crashes or freezes, and I get BSOD errors with the codes DRIVER_POWER_STATE_FAILURE and VIDEO_MEMORY_MANAGEMENT_INTERNAL when the GPU is enabled. However, if I disable the GPU through device manager in Windows, the system works perfectly fine. Interestingly, sometimes the GPU works without any problems, and I can play games for up to two hours without any crashes or BSOD. What could be wrong with my GPU? Is there a way to fix it without buying a new one?

Question by Iyhgz on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.