1. Have to pass on that one. Check for drivers at the maker's site. The worst that can happen is that 3D wont work. Normal video should work fine.
2. You can install as many desktop environments as you want and choose at login. I use either KDE or XFCE
3. You can install any software you want. Debs are native to Linux Mint DEBian Edition. You can install most RPMs (use alien) or even compile apps from .tgz
However, its well to make sure the software is Debian compatible, as most Linux software is, but be wary of stuff from the Ubuntu PPA repositories.
4. http://www.fileplanet.com/126568/downlo ... 5BLinux%5D
if the link dont make it through here, check for linux steam at fileplanet-com.
Look also for supported games for Wine in the playonlinux site.
Wine will typically run many Games as well as m$ office apps. Most moderately sized Win apps will run under wine, but it make take a bit of tweaking on some. Load Winetricks and PlayonLinux. The commercial Crossover office may improve performance. An old trick, which will draw alot of flames, is to install all the Linux libraries for the Win .DLLs and then copy over /system32 making sure NOT TO OVERWRITE *anything*.
This is a tough distribution, and does not break as easily as Ubuntu - assumiing you have used that before, and remember there is ALOT of difference between LMDE and Mint 14 (the last ubuntu release?)
LMDE is really lipstick on Wheezy/sid.
That is not a bad thing. By any means.