My brother was having troubles with his 7970M overheating on his Alienware M15x laptop and so we decided it was time to change the thermal paste. We did a normal procedure of using isopropyl alcohol and a cloth to wipe the thermal paste off of the heatsink and the GPU. We put the thermal pads back on the GPU and applied a small pea sized dot of thermal paste (CoolerMaster Extreme Fusion X1) and put everything back together. We turned on the computer and it didn't boot past the Windows 8 logo. It would just show a back-lit black screen. We reinstalled windows and it was able to boot normally but once it automatically downloaded video drivers, the screen would go flash and then show a back-lit black screen again. It was able to boot to safe mode and the problem didn't occur (probably because it doesn't automatically install drivers in safe mode?) After reapplying thermal paste twice, I noticed there were small bits of thermal paste on the resistors(?). I didn't think the paste would do anything to it but I cleaned it anyway. Didn't help and problem still persists. I was thinking about bathing it in alcohol but I don't think that'd help since I don't know what the actual problem is.
SPECS: Alienware M15x AMD Radeon HD 7970M
Intel i7 720QM
16GB (2x8GB) Corsair Vengeance RAM
PNY XLR8 128GB SSD Toshiba 1TB 5400 RPM HDD
240W Dell Power Adapter
Windows 8.1 64 bit
The 900 series power is insane!