Macbook Air Won't Restart
Older laptop running Mac OS High Sierra 10.13.2. Over last few months regularly gets sluggish; responds well to Restart (local WiFi issues after move to rural area). New problem: Will not Restart. Have to manually hold down power button and then get message "You restarted because of problems ...". No Apple store nearby. Cannot afford to replace right now. Clearly software pollution, so concerned about reinstalling via back up from Time. Hints welcome.
MacBook Air, OS X Yosemite (10.10)