Try deleting the com.apple.systempreferences.plist.
You need to look in your user Library/Preferences for the .plist. Hold down the option key while using the Finder “Go To Folder” command. Enter ~/Library/Preferences. Move the .plist to your desktop.
Restart and test. If it works okay, delete the plist(s) from the desktop. You will need to reset your system preferences.
If the same, return the .plist(s) to where you got them from, overwriting the newer ones.
If you prefer to make your user library permanently visible, use the Terminal command found below.
You might want to bookmark the command. I had to use it again after I installed 10.8.2. I have also been informed that if you drag the user library to Finder it will remain visible.
If that doesn't work, try setting up another admin user account to see if the same problem continues. If Back-to-My Mac is selected in System Preferences, the Guest account will not work. The intent is to see if it is specific to one account or a system wide problem. This account can be deleted later.
If the problem is still there, try booting into the Safe Mode. Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal. This will reset some caches, forces a directory check, and disables all startup and login items, among other things. If the system operates normally, there may be 3rd party applications which are causing a problem. Try deleting/disabling the third party applications after a restart by using the application unistaller. For each disable/delete, you will need to restart if you don't do them all at once.