I upgraded to Windows 10 from 8.1 a few days ago and now when the PC is inactive for around 1 minute the screen timeout kicks in and I have to sign in again even though Windows 10 settings are set to 15 minutes and the Dell Power Plan is also set to 15 mins. I contacted Microsoft and the agent took control of my PC for a while trying to find the problem and reached the conclusion that my chip set drivers needed updating but I have not been able to find out how to do that. I have an Inspiron 660 with an Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz, 3400 Mhz, 2 Core(s), 4 Logical Processor(s) and according to the Dell Web Support all my drivers are up to date.
So I hope someone can please help me resolve this irritating little problem.