how do i extract "track03.iso"

[Megalexxx]

I think dragging your .ISO file and dropping it on your extract.exe program should work too...

But Wayne is right : your surely either don't have the "extract" program, or you don't work in the right directory. Once you're in a dos window, type :
_ "x:" to change to drive "x"
_ "cd dir-x" to move to directory "dir-x"

use that to go to the directory containing both .iso files AND extract.exe and then type "extract xxx.iso".