I tried to download it to my computer which is running windows 7. But when ever i hit the download it pops up with a box that says "Do you want to open this file?". I click open and then it gives me a list of options to open it up to... and idk which one to choose to download it? please help me out!!!

If, on the download screen, it asks whether you would like to open the file or save the file, choose Save File then Display Fusion will save to your hard disk usually in your profile under Downloads.
You should be able to click on it and install DisplayFusion from that.

Alan