[Warner306]

That doesn't look right at all. You should open Notepad and copy and paste the following text:

<playercorefactory>
<players>
<player name="MPC-HC" type="ExternalPlayer" audio="false" video="true">
<filename>C:\Program Files\MPC-HC\mpc-hc64.exe</filename>
<args>"{1}" /fullscreen /close</args>
<hidexbmc>false</hidexbmc>
<hideconsole>false</hideconsole>
<warpcursor>none</warpcursor>
<playcountminimumtime>1140</playcountminimumtime>
</player>
</players>
<rules action="prepend">
<rule filetypes="mkv|avi|divx|ogm|mp4|mov|m4v|flv|m2v|mpeg|mpg|mts|m2ts|vob|bdmv|iso" player="MPC-HC">
<rule protocols="http|https" player="MPC-HC"/>
<rule protocols="daap|rtv|rtsp|rtmp|rtmpe|rtsp|mms|rtp|pvr" player="VideoPlayer"/>
</rule>
</rules>
</playercorefactory>

Save as playercorefactory.xml and move the notepad file to the userdata folder. You need to install the 64-bit version of MPC-HC for this to work.