Suspect the problem is because you disconnected the PATA drives when
doing the install then re-connected to install Ubuntu 9.04. If you
disconnect the PATA drives does the SATA drive boot OK ?

What happens if you only connect the Ubuntu 8.04 drive ?

This e-mail program you don't want to lose the messages from. Does
it have a way of exporting messages to a CSV or some other format that
could be imported by a newer e-mail client ? Would help if we knew
what this ancient e-mail client was too