WIndows 7 is notorious for having issues with finding and installing Windows Updates. There were several KB fixes to help with this problem. Check to make sure that these four updates are installed. If they are installed, and your computer still hangs on install, then disconnect the computer from the internet and re-try the install.
If none of these updates are installed, then you are far behind in your Windows Updates, and you should bring yourself current before trying to install MPC again.
KB3020369 is a pre-req for KB3172605
KB3172605 is to speed up Windows Updates
KB3033929 is needed for Driver Signing