We have an Intel Core 2 Duo, 4GB, 2.66GHz, using OS X 10.6.8 Have 2.57 GB free. We have been using a WD My Book World Addition II for back up. We had a power outage a few weeks ago, and now there is no back ups being done to the WD. I have tried restarting and re-installing the WD, but nothing happens. Doesn't show up in Time Machine, nor does it ever seem to work correctly after I restart it. The light sequence on the front display of WD does not match anything described in owners manual. I have decided to ditch the WD, and go with a 2TB Time Capsule. We are using an Airport Extreme for Wi-Fi now. Will I just be able to unhook the Airport Extreme and WD, plug in, hook up Time Capsule, and follow the set up procedure? I am not really good with computers, but want Wi-Fi, and automatic backups.