I'm a crotchety, 82 year-old geezer with big hands, and somehow or the other I managed to replace the left fan in my MacBook Pro 15" 1211 in about one hour! It was helpful to use a paper-mache egg carton to organize the little itsy-bitsy screw, because if you ever lost one you would never, ever find it again!
I had to use a big hammer occasionally to get things back together, but lo and behold my wife turned on her beloved machine and was very surprised to find that it works perfectly.
Many thanks for your great help and instructive manual!
Sincerely, Doc Botsford