I keep trying different things but the answer is still the same, it looks like it's going to proceed at first but then I get an error message that says:

The System Administrator has set policies to prevent this installation.

I didn't even download this thing until two days ago! I've virus-scanned it and spamware scanned it and it turns up green! I don't know what I can do. Can anyone help me?

If you are not the person who owns the computer (aka the administrator) then get this person to log in and install it for you.

Else, log on to the administrator account with the password you set during windows setup (blank by default) and try running the program then.

Have the admin install it(you arent the only user if that error comes up)

Just follow the instructions from this link:
http://forums.mapletip.com/index.php?showtopic=113287