"What is the safest way to open iPad without cracking its front screen?"に関する回答You have to heat it up. The adhesive will not release without doing so. Take your time and work in sections.
"iPad 3rd Gen Digitizer the same as 2nd Gen?"に関する回答The board sockets (connectors) are the same. The iPad 3 digitizer cable is longer though. So, as stated above, you can use the iPad 3 diggie on an iPad 2 with a couple of folds on the longer cable. However, you wouldn't be able to use an iPad 2 diggie on an iPad 3. The cable just isn't long enough. IndyElectronix
"No digitizer after glass replacement?"に関する回答I had the same problem as well. Turns out that the little pins on the digitizer connector on the motherboard come out VERY EASILY. I'm in the process of looking for a replacement connector. You may have the same issue. Put a magnifying glass on that connector and make sure all the female pins are there.