for lvl 7 here is how i pass it. all in 1 rack starting from the top, basic w/ max ram and high speed, empty space, basic w/ max ram and high speed, empty space, quad ee with 8-16 ram and high speed, empty space, and then a quad ee with ram and high speed. i can get to level 10 but no further...
 "Epic war"){kind=icon}
 "Rack-a-Node"){kind=icon}
 "Destroy All Zombies III"){kind=icon}