Chipping in: I typed the powershell.... command of the first reply to this problem from Sachin in the command prompt (administrator), but nothing happened. What came back is below in the screenshot:
Thank you. That shows what "doesn't work" means. Obviously there is a typo somewhere.
Here is one of the usual references for this technique. Let's look at the syntax given here:
http://blogs.msdn.com/b/notime/archive/2013/10/18/fix-store-app-in-windows-8-1.aspx
Oh. I see. It looks like your first attempt worked but then you overtyped the . for the file extension with a comma? That was a syntax error, so of course that "didn't work".
FYI
Robert