How to re-install game/application that isnt properly installed?

[WPCentral Question]

I downloaded a game from my computer (in .xap format) and installed in my phone. The installation took awful lot of time and I decided to cancel it and I did. But now when I try to install it again through 'Install local apps' option in Stores, it says its already installed. How can I re-install this game?
Thanks in advance.