[shakey234]

From a "Computer Reboots Every Hour" Microsoft Community thread:
"I know this is an old post, but my reply may help someone else coming across this post with this issue. My symptom was exactly the same as Anbisja here. My PC shut down anywhere between 15 minutes and 18 minutes after the hour all day today. It was roughly every 61 minutes for about 8 or 9 hours. I scanned my PC with Kaspersky's TDSSKiller. It found a "medium" risk - sptd.sys in my windows\system32\drivers folder. I couldn't find very much info on the risk online, but I decided to delete it anyway using TDSSKiller. After that, no more reboots. The reason i doubted it was any kind of heating issue was because of how consistently the reboot was happening every hour. A PC doesn't get hot every hour for 8 or 9 hours in a row. If it restarts from overheating, it should do it again within a few minutes. Anyway, hopefully this helps someone else out there.
-Chris"
Source: https://answers.microsoft.com/en-us/...c-68b599b31bf5