Eboy, you clearly have good depth of knowledge on issues like this and know what you are about so forgive me if I state the obvious.
I've done something similar using Partition Magic and a new HD that was much larger than the original.
Using PM from the system disk C: I partitioned the new drive to include a partition the same size as the original (40GB in your case). Then I "cloned" the whole of the original boot partition to the new drive into the space taken up by the fresh partition. Then, and this was what took me two goes, I made it "Active".
Swapped over the jumpers to make the new HD the Master. I booted just fine.
Then used PM to tidy up the partitions and format the remaining space.
I'm going to search for where I reported all this and I'll be back...
Okay, try these two threads:
http://www.pprune.org/forums/showthr...threadid=54129
http://www.pprune.org/forums/showthr...threadid=54041