**Be sure to read everything first and ask any questions if you don't understand any of the steps.
Since it was happening before sure sounds like a plist issue. We try to to move the plists that control screen saver settings / logout / that way when you log back in the system will re-create the files. In any event this is fully reversable by moving the plist files back to the folder preferences folder...
Here is how you can do this:
-->Lets create a folder on the desktop and call it screensaver plists (this will be used to backup the currect preferences files)
-->Open finder
-->On the menu bar click on Go
-->hold the option key and you should see "Library" come up click on it-
--> now you should be inside the user library folder aka ~/Library
-->Open Preferences and locate the com.apple.screensaver plists... Take a look at the screenshot so you can see what the files should look like the only one that is identical is com.apple.screensaver.plist the other ones may not look exactly alike but still have the word screensaver...
-->Don't delete these files simply drag/drop into the folder you created on the desktop earlier
-->Now go ahead and logout > Apple on the top left > Logout...
-->Log back in and see if you screen saver comes on automatically now.
