My name is Debbie. Mod Edit: Removed spammy comment - Hamluis
Follow the steps mentioned below and check if that fixes the issue:Step 1:
a. Open control Panel (Click Start) and go to Administrative Tools.
b. In Administrative tools open Local Security Policy.
c. In Local Security Policy right click Software Restriction Policies and click “New Software Restriction Policy”.
d. Now Left click on software restriction policies and in the right-hand window you should see enforcement.
e. Double-click on enforcement and set the policy to apply to “ALL USERS EXCEPT LOCAL ADMINISTRATORS”Step 2:
Now restart your computer and check if Media Center is enabled.
A. Open Default Programs (just type that at the Start menu), and click 'Set program access and computer defaults.'
B Expand 'Custom', and make sure that Windows Media Center is both listed (in the 'choose a default media player' section), and the "enable access to this program" check box is ticked.
c. If it's there (but not ticked), tick the box, and hit OK.
d. If it's there (and is ticked), un tick it, OK out, reboot.
e. Go back in, and tick box.Step 3:
Additionally, check the following settings using the Registry Editor.
a. Go to Start, type "regedit" in the search box and press enter.
b. In the Registry Editor, click the [+] icon to expand the tree list on the left.
c. Browse to the following location: HKEY_CURRENT_USER, SOFTWARE, Policies, Microsoft, and select Windows Media Center
d. On the list to the right look for an item named Media Center. If it is there, check the Data column and ensure it is set to zero . If it isn’t double click on the item and enter the number zero  in the Value data field then press OK.
e. Next, browse to this different path then check the Media Center item and adjust as needed as described above: HKEY_LOCAL_MACHINE, SOFTWARE, Policies, Microsoft, Windows Media Center
If you made any adjustments, restart your computer and try opening Media Center.
Note: If one of the items doesn’t exist, that’s fine, just let us know.
Registry disclaimerimportant: This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows
For further assistance please reply
Edited by Orange Blossom, 04 August 2012 - 09:01 PM.
Minor edits - Hamluis. Fixed BB code.