after go back to a restore point an scan the TV channels, I retrieved my WMC.
as administrator I had to change the special rights of a registry key. descripted here:
- restart, do not start wmc, this will mix up the WMC settings
- log in as administrator
- Windows Key + R type Regedit
- Navigate to Key: 'HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Media Center'
- Right click -> Permissions.
- Double Click INTERACTIVE
- On the Right Hand Side, click on "Show advanced permissions".
- Check these two On: Set Value and Create Subkey.
- After the change: all but the top one [Full Control] are checked on the Left, just the bottom one [Read Control] is checked on the Right.
- exit Regedit.
Open WMC normally