There may be a shortcut to the resolution adjuster in the Start\Programs menu near the shortcut to the game exe. I don't know since I don't have the game. But if it's there, that would be the easiest way to get to it.
The game probably installed in C:\Program Files (or C:\Program Files(x86) if you have 64bit Windows). You can find out where it is for sure by right-clicking the game's shortcut on the Desktop and choosing Properties. The path will be listed on the first or 2nd tab.
If you don't know how to use Windows Explorer to browse to a game folder, you should probably watch a few videos to see how Windows Explorer works. Here's one, not necessarily the best one.http://www.youtube.com/watch?v=Hdfv7SvQeXs