I find that my AEs are very finicky. If something changes in the network, or they've been off for a very long time (greater than a week), they need to be reset as they don't connect well with the network. Go figure.
Yes, there are options in the set up utility that will "modify" the way the AE will work. It can either be a print server/itunes player or an extension of internet + print server/itunes player. The cool thing that I did not know is that it can actually act as a wireless bridge! Lucky me I bought two of these babies two years ago. My new room does not have a wired internet access, but thanks to the AE, I've got internet (bridging from fiance's office to mine)!