Until recently, my woman's PC would go to sleep (or whatever state it is) when left unattended, but would come back reasonably quickly if a keyboard key was touched, or the mouse moved. Used to do the latter as didn't lick the thought of it accepting keyboard input and putting something somewhere.
Now though, the mouse doesn't wake the PC up. Keyboard still does but it's slow to come up. Have checked it in the device manager and the 'wake up PC' box for the mouse is definitely ticked, so it isn't that.
Have you checked through your power plan options to see if something has been changed. Right click on the desktop - select display settings then power & sleep.
If u look In windows options it will give options to do system reset to take it back to factory settings but you will loose everything, but should be option to clean the hard drive without any data removed so will just get rid of any "rubbish" on the hard drive