How is your IP address assigned?, blah...
As far as I know, the IP address of your machine is completely
irrelevant to MS's key generation mechanism. I will not pretend to know
everything about it, but I believe that there are 6 items that are
checked: the CPU, motherboard, amount of RAM, the HDD, the MAC address
of your network card (if you have one) and there is something else that
I have forgotten.
The MAC address is hard-wired into your network card and so will not
change if the IP is changed. Therefore you do not need to worry about
the IP address changing for re-activating it.
What I suggest you do is to phone MS up to activate it (as opposed to
automatically doing it over the net) and write down the configuration of
your system (including the order in which you installed things), the
number that you have to give them and the number that you get back. This
means that you should be able to re-install Windoze on your machine
without phoning them up again, provided you follow the exact same steps
and use the exact same components as before.
Don't forget to note the particular minutiae of your machine like which
cards go in which PCI/ISA/whatever slots, which BIOS revision you have,
which IDE devices are assigned to which channels (also master/slave
arrangements), the partitioning of your HDD(s) and other suchlike.
Possible tips would include not installing network cards/disabling
onboard LAN (so you are not tied to a particular MAC address) and having
the bare minimum of hard drives installed so that the key you get is as
general as possible. Be sure to test your system first to make sure that
it works well, as you may be activating a duff system otherwise. You can
then wipe the HDD and start again, activating 'doze on the most general
combination possible.
I have never tried this (haven't had the guts yet) but it is possible
that windoze will want to be re-activated upon adding a certain (don't
know how many) number of measured components. Therefore this method is
not entirely without risks.
Yes, do reactivate them unless you just want to try Linux
instead?
Or that. In fact, go get Linux now and stick it on a secondary hard
drive. The worst that you will suffer is a bit of lost time installing
and configuring.