Checking the hardware is a good wheeze. If the PC is useless, nothing to loose.
I would say be methodical and do one thing at a time and try the switching on after each prod. Or keep meticulous records. I wouldn't but then I am a techie, and would structure from perceived priorities. Someone less confident would need a methodology that assumed little knowledge. I would give it no more than a 20% chance of improving things, but I would do it.

Changing the clock (etc) battery would not be an expensive safegurd. After the above.

It is interesting, when I was designing with industrial PCs the motherboard was not especially industrial, fairly ordinary. But every connector had hot-melt glue blobbed strategically to hold the connector in place.

FWIW I have just read an article on why Win10 is better than 8 or 7. and the only possible actual advantage they put forward was the inability to switch off updates. Which is not an advantage IMNSHO. I have had updates crash an hour's work in order to auto update. I now update Win7 at switch-off, if appropriate. And updates are rare now. All other listed Win 10 advantages were Xbox or something marginal like "bit" faster on some but not all apps! But if you are buying from new Win10 is wot U git.