Thank you for the answer and the good piece of advice, I may well end up doing this if I can't move the full PC.
The reason why I want to move the machine is that a one phase only migration would be nice and I will juts have to re-enter the W7 code that was provided with the PC version.
I created a guest account on the PC for other reasons and logged through this account and WHAT A SURPRISE !
The PC Migration client poped-up at the first boot but only with the Guest Account, the Admin one doesn't work.
Unfortunately when the 4 digits code were keyed-in on the iMac the connection, once again, could not be established.
Obviously the issue is on the PC side as, today,I can't connect to the PC via the Finder, which I could do the other days.
Windows is strange
: one more reason to move out.
Thanks for the comments.
Marc.