Hi, this can be hard to diagnose as there may be no fault reports.
Do you actually experience a crash? Sudden shut down? Or just freezing?
History: (so often omitted by posters)
- when did this start?
- what happened before this started?
e.g. did you upgrade/change/install/uninstall something...
As was prompted by the forum when you wrote your post to save us typing the question, what is your Windows build number?
Try
Whocrashed (free) - see if it tells you anything
Look at your Reliability History - do the red x's correspond with the time of any freeze?
Elimination:
Try a clean boot (Google if unsure). Over a sufficiently long period, do you experience any problems?
If you don't, you may now have a clue.
If you do, boot to Safe Mode.
Over a sufficiently long period, do you experience any problems?
Disconnect/remove your video card. Over a sufficiently long period, do you experience any problems?
Try running
Enable and Disable Driver Verifier in Windows 10
Are you overclocking?
Is your RAM all exactly the same?
Have you made any hardware changes that could account for this?
Consider possible PSU problems.
Run a RAM test.
There are various stress test programs such as Heavyload and Prime95 you can run.