Check your screen saver and your power settings. Right-click an empty area of the desktop and click Properties-> Screen Saver. For power settings go to Control Panel -> Power. One of those two is likely your problem.
In case you didn't know, you can download Start8 or Classic Start and make Windows 8 look and feel like Windows 7 if you'd like.
upgraded from windows 7 Pro to Windows 8 Pro and all works well except:
The laptop signs me off after 15 second of inactivity and I have to do the sign-on again. It is driving me crazy. I have searched settings but cannot find the correct one. Can anyone help?