I have a Macally 7-port powered USB hub hooked up to my Macbook Pro. Four gigs of RAM in the Macbook Pro. Last year's model. When I attempt to boot up with the 7-port device plugged into one of the Macbook Pro's USB ports, I get the usual responses...sound, Apple symbol, blue-ish screen, but it never gets to the log-in screen. If I unplug the 7-port device, the computer boots up properly. Plugged into the device: scanner, printer, external DVD writer, sometimes iPOD cable. Any suggestions as to what may be the problem? Thanks!