Windows 10 sudden blank screen

Question

Lately i re-installed Windows 10 to get a fresh OS. After i have installed and updated everything including drivers, it worked fine until few hours later, screen went blank with no cursor or anything at all, just blank.

• Not necessarily a black screen, sometimes colored [black twice, dark green once]
• RAM LEDs indicated no activities although last time i was rendering some videos which means the whole OS stopped running (PC still on)
• Re-installed latest drivers (i don't think it's a driver issue)
• Video card is fine, i tested it on another machine for a whole 72 hours

What could be causing this problem?

Edit:

After i reset/restart PC, it works fine until another couple hours later.