You could reset the registry setting to see if it fixes the problem.
Copy the following setting and save them in Notepad. Then save it in a file with a .reg file extension. e.g., ScreenSaverReset.reg
Then run it or manually set them using Regedit.
[HKEY_CURRENT_USER\Control Panel\Desktop]
"ScreenSaverIsSecure"="0"
"ScreenSaveTimeOut"="600"
"ScreenSaveActive"="1"
[HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Control Panel\Desktop]
"ScreenSaveActive"=dword:00000001
"SCRNSAVE.EXE"=-
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
"NoSaveSettings"=dword:00000000