Youtube has several videos showing the G75 tear down. Pasting a CPU/GPU is the part you should focus on. There's a video you can find where the poster demonstrates the different methods (dot, line, cross) of application and how it looks when it spreads as you reinstall the heatsink. Getting to the components isn't difficult (use cups or an egg carton to separate the different screws, take pictures and make sure to observe electrostatic safety - ground yourself, touch bare metal parts of the laptop chassis before handling EPROMs/RAM/GPU/CPU/etc) but if you get an air bubble in the paste, you'll be doing it all over again. The CPU and GPU are highly visible components, they'll be directly under the heatsinks. The G75 has two cooling arrays, one for the CPU and the GPU, each with their own fan. Like Zygomorphic said, take your time and don't rush. Do it right so you only do it once.
