I tried installing Demigod on Windows XP, and - just my luck - my computer freezes up on me, mid-installation. After I restart it, and attempt to autoplay Demigod to install it, it instead asks me to play it. I thought to myself, as I wasn't watching the installation screen when the freeze occurred, "Huh... I guess it managed to fully install before the freeze."
Well, it didn't. It went to a black screen, with some white lettering in the lower-right corner (completely forgot what it said), and didn't get any further than that. So, I started deleting everything related to Demigod off of my computer with RegCleaner, so I could reinstall it.
That didn't work. Now, every time I try to autoplay it, it asks me to install it. Then, the install wizard "verifies the contents of the setup package." Then, it asks me if I "want to uninstall the application and all of its components." If I select no, nothing else happens. If I select "yes," then it asks me to wait while the setup uninstalls Demigod. This process lasts less than a second before another screen appears, telling me that "the setup wizard for Demigod has failed: "Fatal error during installation". Please check your settings and try again." Then, all I can do is hit finish, and nothing further happens.
I have scanned my computer as thoroughly as I know how for any remaining components of Demigod, but only a single one remains. When I go to my control panel, then to "Add or Remove Programs," a file named "Demigod" appears on the list. It has no information listed, except that I use it rarely, and has a little icon of a box-shaped monitor and computer tower, with a cd-disc at the bottom (a common icon for installation programs, as I understand). I have no way to move or manipulate this file in any way, and I'm pretty sure it's what's standing in my way of installing Demigod.
Also, I while looking for any previous topics that could offer a solution to my problem, I noticed that one of the more common fixes is "download it from Impulse." Well, I'd rather not, as I'm confined to using WiFi for my internet connection. I'm only allowed so much bandwidth per month. 
Would anyone be so kind as to help me with this? I've got no idea what to do at this point.