My old A500 has not been used for several years, but it powered up perfectly a couple of weeks ago. Monitor came on and everything seemed fine. The first screen appeared (the hand holding the workbench disk) and so I inserted one of my working copies. The disk drive spun but nothing happened. I tried two other backup copies, but nothing happened. Then I tried to boot some games that don't require workbench, and they didn't boot either. I don't know how to try to boot from the external drive either. It seems that the internal drive (DF0) isn't seeking the data. Can I boot from the external drive?