Uncheck everything in msconfig>Startup except your AV and gadgets/stickynotes if you use them. All others are freeloaders on your RAM/CPU, Startup and can spy on you. Startup Programs - Change
Next after several restarts, in msconfig>Services select Hide All MS Services to see what is running without your knowledge. Turn it off in its Program preferences or uninstall.
Finally if the problem persists, look at scheduled tasks by typing Task Scheduler in Start Search box, then under Action Column, highlight Show all Scheduled Tasks, highlight any you don't want and End Task.