OP seems reluctant to use diskpart for some reason despite me mentioning giving it a try even from the start... It would certainly stop the disk being assigned a letter in WinRE.
Strictly speaking, the disk should be cleaned and formatted on a Windows 7 installation anyway as best practice, due to the slight changes in the NTFS file system specification over the versions, assuming the old PC wasn't running Windows 7.
Zen 8000 Pro
Edited by Pipexer (Mon 09-Apr-12 20:32:39)