Is there a way to know if the computer restarted by itself overnight?

My computer would occasionally make a short buzz sound (1/2 second), then get a blue screen and restarts. I took everything apart and found my video card, Nvida GeForce GTX 660, to be full of dust. I took it apart and cleaned it. Now, I want to know if it is fixed, and I'll know if the computer no longer goes blue screen and restarts. But if it goes blue and restarts while I'm asleep, how will I know. I generally run it 24/7 but restart the system weekly to refresh the RAM (32GB)

Len

Try event log or for a quick check see the uptime Find System Uptime in Windows 10 Windows 10 General Tips Tutorials

Thank you for your prompt and accurate answer. - Len

In the Event Log look at System under Windows logs. A bluescreen will produce Event ID: 1001, Source: BugCheck.

You can filter the log to find all occurrences, in the right hand panel click Filter Current Log and tick 'BugCheck' in the drop-down list for 'Event sources'.