I need some help getting a game to run on Windows 7.

I recently bought Star Wars KOTOR 2 from Amazon. I installed it with no trouble whatsoever, then tried actually playing the game. It just won't run. It didn't show any error messages at all, it just wouldn't start up.

I Google'd it extensively and eventually came to think my problem was it wasn't working because the game was made for Windows XP and not Vista or Windows 7. (This would make sense, since apparently my brother wasn't able to get Neverwinter Nights, another old game, to run on this computer).

I found a supposed fix for Vista users that replaces a file to make it more compatible with Vista. I tried that, hoping it might work with Windows 7, and it didn't change anything.

I had no idea what to do from there, so I came here. Keep in mind I'm kinda new to PC gaming (been using Macs for a while now) and I don't know my way around Windows very well.

My last option is to maybe install Windows XP into my Mac with Bootcamp and run the game from there, but I'm kinda hesitant to get an OS just for one game, especially if I don't know if it would work.

Any help at all would be greatly, greatly appreciated.

EDIT: I should probably point out that I'm running Windows 7 with Bootcamp on an iMac. I'm not sure if that has anything to do with it (I have all the hardware requirements to play the game), but as I said I'm pretty new to PC gaming.