The Technical Preview which Microsoft has released yesterday doesn’t have WMC.However you can still add WMC to it.Here are steps to do this:
1.Click “Add features to Windows Technical Preview” present in Windows Technical Preview version.
2. Put your Media Center product key (which you used earlier during adding WMC to Windows 8 Pro).
3.If it’s a valid key it will show ‘Your key works…’
4.Accept the license terms which will allow to add new features.
5.Adding features continues.
7.Now you will find WMC has been installed and working fine.
[Note:Adding WMC will change the name from Windows Technical Preview to Windows 8.1 Pro with Media Center.Evaluation copy. Build 9841.You may experience random bad behavior.]