Len:
Steve is essentially correct in that the likelihood is you will have to
undertake a Repair install of XP following the motherboard installation. But
let me add a few comments...
While a Repair install of the OS will probably be necessary, that isn't
always the case - even when the new motherboard is a completely different
make & model of the one that is being replaced. Sometimes you luck out in
that the system will boot straightaway following the new motherboard
install. Although unlikely, we've experienced this a number of times.
Assuming you need to undertake a Repair install of the OS the process is
relatively straightforward. It would be roughly akin to making a fresh
install of the OS, but in nearly every case your existing programs &
user-created data would be retained. Notice I said "nearly". While it would
be a rather rare situation where data would be lost or corrupted as a result
of the Repair install, and as unlikely as it may be, it *could* happen.
So if there are any programs and/or other data on your present drive that
are absolutely crucial to you and you could not tolerate its loss, then I
would strongly suggest that before installing the new motherboard you first
either make a clone of your existing HDD (using a disk imaging program) or
use some other means to copy whatever data you want to some other media.
While I really don't want to overemphasize the possible negatives in this
situation because in the overwhelming amount of cases where a Repair install
is undertaken there's no problem with loss or corruptions of data occurring.
There are a number of websites that contain step-by-step instructions for
undertaking a Repair install. Let me assure you that it's not a difficult
process and not terribly time-consuming. If you do a Google search on "XP
repair install", you'll be pointed to many of these sites. Here are a couple
beside the one Steve mentioned...
http://www.webtree.ca/windowsxp/repair_xp.htm
http://www.geekstogo.com/forum/index.php?showtopic=138
Assuming the Repair install is successful, you should use your A-V program
to immediately check out your PC for any virus infestation. Also, you will
need to download/install *all* the MS critical updates since SP2. (I'm
assuming that if the Repair install is necessary, you will be undertaking it
with a XP CD that contains SP2). That, of course, is one of the downsides re
using a Repair install. It's usually an onerous task to download all the
Critical Updates from MS especially if you have a dialup phone connection
rather than broadband.
Anna