basicall all you need is to start dosbox,
then type (always without the " of course):
"mount c c :/fg"
(this is for the case your fg-folder is on drive c, else type in every other path - this mounts the folder fg as if it would be drive "c" in dos)
and then
"c:"
(to change to drive c (which is folder fg on c
)
then type "FG"
(alternatively you may type "cd exe" and then "setsound" to start the setsound.exe - and set your sound.) - after that leave with "cd .." and type "FG")
in the dosbox.cof - file (you edit this file from XP (normal windows)) you can set the "sensitivity=100" to "sensitivity=200" in order to speed up the mouse.
as mentioned i still use FG in XP and it works good, so no real need for dosbox for this one though
but this is as i use it fortoher games. if its to slow you may try to increase the "cycles" (in dosbox.conf)