If there is a DWoRD Value such "NoDispScrSavPage" with a data value of 1 this will disable the screen saver tab.
Change the value to 0 or delete it to see the tab again.
Start->Run,type gpedit.msc.
Navigate to user configuration->Administrative templates->control panel->display.
On the right pane,disable "Hide screensaver tab" and enable"screensaver".