I ran into a similar problem a while back when using some drives that had partitions on them that were unknown to the OS of which you want to install. My fix for this was to delete these partitions with either DELPART on a bootable floppy disk, or use a bootable Linux OS to delete the partitions. I then was able to boot the system off of the OS that was to be installed on the old system and the hard drive was bare as if from factory, I then was able to make necessary partitions and install the OS clean and in no time was up and running.
At my current gov job we still use the old 64-bit DEC Alpha's with DEC Net and OpenVMS OS. They are solid running systems. Its been a long time since I ran NT on a Alpha 200, but I know that NT 3.51 worked back in the late 90s at a prior job that had them. Unfortunately there is very limited OS support for the 64-bit Alpha's.
Edited by goldfist, 26 December 2013 - 11:17 PM.