Hi Mondo, welcome to NST.
I can recommend you read the 2 links in this post,
http://neosmart.net/forums/showpost....87&postcount=2
which will explain the bootloader chaining, so you understand what's supposed to happen(link 2), and what's causing the NTLDR error (link 1).
I don't know why your Vista doesn't boot identically each time though !
Disk lettering is an internal construct (in the registry) on each system and won't necessarily agree from system to system, unless you take steps at installation time to make them do so.