Ok to respond to both...
I tried safe mode, and get the same error message... I tried uninstalling my windows installer and installing the newest version (which is the version I had anyway) to no luck, same message.
Basically I've tried everything suggested.
Do I have any other versions of the setup.exe on my computer? No.
What sucks too is that if I'm going to miss out on the discounted rate, because I can't get this thing to work and try, and surely it wouldn't be smart to buy it if I can't get it to download

...
Oh, and yes, I'm attempting to install it by double clicking... Though I've also tried right clicking and choosing open.
Are there any good installer programs out there that people know of that I might be able to use? Preferably free ones?