My digitizer is not working without the cover glass in place

I am in the process of refurbishing an iPad 2. A friend of mine from another country gave me his to take to the Apple store to get it replaced, but it turns out that he'd already replaced the cover glass and went from the white border glass to the black border glass. Needless to say, when the Genius Bar found that out by looking at the serial number they wouldn't touch it. Fair enough I said, and relayed that information to my friend. I asked him if he wanted me to send it back to him and he said forget it, and asked me to buy another one for him. Not a problem I said. Well I decided to see if I could get this thing to spring back to life. It appeared that the dock connector was dorked up, so I replaced the dock connector after removing the cover glass, and breaking it in the process. No matter I said, so I replaced the dock connector, and I actually got the iPad to take a charge. Before the repair, it was totally dead and would not take a charge. So I'm trying to hard reset the think so I can restore the settings, and I haven't replaced the cover glass because I don't want to sink any more money into it unless I can get it to work and restore the factory settings. So I charged it up and it took a charge, (about 17%) The screen saver came up, and I got the slider to come up, and I'm not able to get the slider to respond. Again, I don't have the cover glass on it, and have been carefully using my finger directly on the digitizer, but again, it won't respond. So again, do I need the cover glass in place in order to get the digitizer to respond?