System Boots the drops to low power

[chaos719]

Hi have a pc which just stopped working. When I boot my system It powers up goes through the bios without a problem, bios is accessible. Goes into windows and before fully loading Windows the power drops to enough to run a few fans. I can boot fully into safe mode. I had another power supply and it booted and did the same. (Unknown if it is a good spare)

Win 7 ultimate x64
I7-6700k water cooled Corsair H50
Asus z170-e
Asus geoforce gtx 1060 6gb
Evga 850 watt titanium power supply
2ssd
2hd
1dvdrw
1 bdrw external drive external powered
More about : boot powers low power

 

[darth.gabby]

What do you mean by the power drops down? The computer shuts off, leaving only the fans powered up?