Have win 8.1, disabled UAC and still no luck, VLC works fine and strangely windose media player works fine but MPC takes forever to load and seek a video. Mainly dealing with MKVs,MP4's.

I have uninstalled it twice and reinstalled no luck there, using K lite codec mega 10.4

I have managed to get by most of 8.1's quirks but this one has me stumped.