Sorry bud, wish I could help, I haven't seen that issue yet, and am on win7 as well, never needed to do anything special beyond that one windows update...
Wait, IIRC, you said you tried it but it wasn't for your system? Do you by chance have a 32bit version of windows 7? Maybe you need a different version of that update...? Other than that or maybe a codec issue, I am out of ideas atm.
I don't know, while I haven't tried that yet, as I have yet to get anything far enough along to be worth trying, so there might be more to it than I know, but unity has the option to do almost every platform. There could be some other issue though, like the UI might need to be adjusted, or something else with the design that needs to changed to make it work, like mouse over not being a thing in touch screen interfaces, making the hint system difficult for one example.