EULA (again, sorry!)

OK. I buy a retail copy of Vista and install it. Then six months later I
upgrade the hardware, including mobo and HDD. I then re-install (as one
transfer to new hardware is allowed according to the EULA). Six months after
that, I transfer the licence to my dad (living in the same house as me). I
then upgrade my PC again, and dad installs the OS onto my 'new' machine
(it's now his copy after all, he can install it on whichever PC he wants).
That's now three different PCs/two transfers to new hardware.
Have I missed something here? Does it mean that if I've done one transfer to
another PC, I can't then sell/give away my copy as I've already done two
separate activations?

It says that the original owner can make a transfer to new hardware once,
and also says that he/she can also transfer the licence and software to
someone else once (unless I've read it wrong). It's all very confusing!