Windows+X shortcut key doesn't work anymore in Windows 7 x64?

"There are a few ways of disabling the Windows Mobility Center and it is hard to know how it was done in your case, the most common one is by a registry key. To restore (If it was done this way) Do the following:

Open up the Registry Editor and expand to:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

Take a look for the key NoWinKeys and simply delete it.

Here is a .reg file that can be directly run to do the above job.

If this doesn't work, please say and I will try to write a guide for some of the other methods."