I understand that you have Windoz on one HD
and Ubuntu on a 2nd HD. Correct?
And you want to "replace" Ubuntu
because Ubuntu no longer supports your graphic card.
It would seem that if Ubuntu will not support your card,
then Mint will not also. But if your tests prove otherwise, good.
Have you tested your replacement OS (Mint, unknown version)?
I would view YouTube videos on Mint (and other OSs) installation.
I would download and burn a live CD/DVD and play with it for a while,
before attempting installation.
I recommend your download GParted, and burn it to CD. http://gparted.sourceforge.net/livecd.php
Run it and wipe your Ubuntu HD completely.
Then you should not have any problem installing Mint
to the 2nd HD.
I recommend Mint 13 over Mint 14. Mint 14 isn't toilet trained as well as 13.
And Mint 13 has Long Term Support (LTS). 14 has no LTS.
Jim1938 == Mint 13 xfce 64 bit on diy box.
Wirth's law - Software is getting slower more rapidly than hardware becomes faster.