Screen (not Lock Screen) Timeout Stuck at 1 Minute

In the end, I had to dig through the output from Process Monitor to see what other settings might be getting set (by who-knows-what) when I changed my screensaver settings. I found a registry key I haven't seen before:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\InactivityTimeoutSecs

It was set to 60 (seconds). I updated it to 900 (15 minutes), and it worked!

I still don't know how that got set in the first place, or why my screensaver timeout kept reverting to 1 minute (it doesn't anymore, since I changed that registry key), but if you have any ideas to help explain it, I'm all ears (or eyes, I suppose). Still, since this caused me so much time and frustration, I wanted to post what finally worked in case it can help someone else.

i had this issue also, it turned out it was getting the mobile device settings from exchange and locking like a phone would. tested it out by editing the exchange setting and that was it. turns out i must have miss-clicked on windows mail and setup my email account and it started pulling these settings.