1st of all, please know, the 64bit app affects playback in Media Center
The 32bit app affects most other players such as the default WMP
If you are not a LiveTV user, I suggest that you disable the Microsoft Video decoder on the SWAP TAB. Test.
The suggested settings disable Media Foundation on the SWAP TAB
This is benificial for M2TS playback but can break MP4 playback.
If the 1st suggestion didnt work, or is not for you,
press [Reset All]