My PC self-reboots: Faulty Uninterruptible Power Supply (UPS)
Cause number 3 is a faulty Uninterruptible Power Supply or UPS. This usually happens when the PC’s UPS has outlived its two year warranty. This happened to me years ago when I was working on my undergraduate thesis. My PC would self-reboot at the most inopportune times. The cause of my agony was a simple faulty battery. The best solution to this problem is to replace the UPS when it turns 18 months old. This will prevent having your work interrupted by a sudden reboot only to find out that you had not saved any of your data for the last hour.
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