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The other issue I am having is that I can't get Amiga Explorer to connect to the serial port on the 2000. (Yes I have bought a good quality null modem cable and have set all the settings according to the program but still no dice..)
Can you confirm the cable and null modem on another computer? Believe it or not I have found bum RS232 cables in the past the visually looked fine. Check the obvious, make sure the serial port is enabled in your PC BIOS and COM1 is configured right in Windows.
Next, how many colors is your workbench? Set Workbench to 4 color and try again. On the Amiga 500 you would totally kill the serial port if you set Workbench colors too high. If memory serves me correctly, the A2000 is the same.
Finally $90 for a A2000HD is a darn good price nowadays! Enjoy!