The screenset should work fine on that version.
Your Mach3 license is good for all versions of Mach3. The latest version is here, but I actually use an older version than you are using (I think 3.042.020 or .029)
http://www.machsupport.com/wp-content/uploads/2013/04/Mach3Version3.043.exeIf you are using the parallel port, you'll need a 32 bit version of Windows 7.
I have a spare computer with nothing on it excepted windows XP I down loaded my Mach3 but when I put the 2010 screen set in I don't get full graphics.
What do you mean by "full graphics". If backgrounds are missing, the screenset is installed in the wrong place.
Re-installing **should** fix it, IF there's a problem. but I can't guarantee that it will, or that it won't make it worse.