i need to figure out a way to transfer files from my old pc ( with a 1.1usb port) to my new imac... external drive i bought( to backup all my pc files) does not show up on desktop when i plug it in my pc. any recomendations on a drive that will be compatible with both pc and mac that will also work with my old usb? the external drive is formated for windows but it doesn't show up on pc desktop when plugged in. Could my usb port be too slow? thanks