Iv had this issue before with Maya in particular.
Make sure, as you mentioned your computer requirements are equal to or greater then expected.
AS WELL as you have a few gigs (like 2 or more) over the requirement for the entire installation (So lets say its 10 gigs, make sure u have at least 13 free) -- This is because that last file or 2 is has to download, some programs like to just drop a extra 800mb of like readme's and manuals and crap no one ever reads or needs. That could be causing the problem too.
If you have already done that, then first of all:
Is this a legit copy? If so, is it hardware or software legit? (By that I mean do you have the CD ur using, or did you buy the downloaded online from their site?)
If it is a hard-copy (CD) then it might not need to ask you for a key since it would already be automatically registered into the actual drive itself. If it doesnt, then launch the program, go to "Help" and click "Register Product" or whatever it may say, and enter the key from your CD case if its already not "registered"
If it is a soft-copy (bought it and downloaded it) then after the location page (Where ud like to save it) it should ask you for the code or if you want to use trial (if it doesnt, then uninstall it, and re-run it again -- its on automatically install as a "trial" -- I dont know how to fix that, but you could install it as a trial, then after, launch it, go to "Help" and click "Register Product" or whatever it sais, and enter in your key) enter your key, then press next, at which point the download will start and depending on your computers installation speeds, it might take a bit... After, you should get a confusing screen.
The screen will be like the installation screen, but with just a cancel button, and just show the product you downloaded (so Maya) and give a down-arrow, with a few stuff it may of missed... It works, it just didnt put like a useless dll or 2 your probably never gunna use anyway.
If its an illegal copy, try a different torrent/torrenter, its possible its corrupt.
If all else fails, youll have to completely remove it, and then downloadable and re-install it, dont skip those pop-ups, sometimes they have something important to say.