Screen going black after a few moments of usage

Sep 23, 2018
1
0
10
Specs:

3.50GHz Intel i5 6600K CPU
16 Gb RAM
ASUS 1070 8gb GPU

Hi. About a month ago I bought a new gpu and cpu to upgrade my pc. When I did upgrade both items I started having problems. As I would be perform any action (like just browsing google, or playing games) my monitor would turn black and there would be stuttering (both auditory and visual). It’s been driving me insane. I’ve tested the GPU on my friends P.C. and it works fine. I’ve also ran tests on my disks and my ram. All of my drivers are updated. I took it to a pc shop to check it out and they said it was the GPU however it ran perfectly fine on my friends Pc for several hours, almost a full day. Could it be the CPU? Or maybe my motherboard? I want to be certain before I splash out again for a new one. Any suggestions would help me massively. Thanks