Gears of War unable to install due to previous failed installation

[scionreaver]

I was installing GoW for the PC, and was to the point where the installer was at "Decompressing old files" when the install got stuck and didn't move at all for quite some time. After a while, I decided to end task it and try again, but when I tried to install again, it told me that GoW was already installed (and true enough, 9 gigs or so was installed on the system), but not enough for the whole game to run. In all my wisdom (sarcasm), I went and deleted all of the local files in program files\microsoft games\gears of war and ran the install again, but like last time, it told me to go to the control panel.

I went to add/remove programs, and Gears of War was on there. I tried to uninstall it, but whenever I tried, it would tell me:

Error 0x80040702
Failed to load DLL: FirewallInstallHelper

Setup will now terminate.

before it takes me to the install menu where it says the uninstall has been interrupted and could not be completed. This was a total "oh crap" moment. I started up Windows Install Cleanup and went and deleted the Gears of War install files, as well as went to regedit and deleted all of the Microsoft Games folder entries. Now when I try to install it, it keeps asking me if I want to remove all files, just like the uninstall. When I click yes, it gives me the same Error 0x80040702 window.

Help, please?