Strange.... If your installing a new hard drive, do you already have a partitioned & installed HD on the Miggy or is this a bare drive & you just booted from the Install disk?
If the latter, your Install floppy should not have been asking to save changes to the Disk!? HD Toolbox does ask if you want to save changes when you add or remove a hard drive & it seems strange the Install disk is writing data there.
You should just be able to Boot with your Installer floppy, run HD toolbox, partition & configure the drive, save the changes to the drive (NOT RAM), reboot with the Installer Disk, format the partitions & then Install the OS. The only complications are if using SCSI as you need to know what SCSI.device name to use in tool types.
Tsk tsk if you didn't have a back up of your Installer disk, but it writing to itself doesn't seem quite right!
Some info on your Miggy would be good too. Is it IDE or SCSI, name of SCSI device, OS version, ROM, hard drive make & size,...blah blah.
This thread might be moved as it should really be a Hardware topic & not Marketplace.
