A new harddisk must be prepped before it can be used.
Boot the computer with the 3.1 Install disk and run HDToolbox. Let it read the specs from your harddrive and save them to disk. Reboot again with the install disk and this time format the harddisk. You then can begin installing WB3.1.
I don't think you need the 7.0 ROM on the A2091.
