Since you will be getting a new motherboard and CPU in the near future,
wouldn't you be better off installing from scratch using the OEM version of
XP+SP2? Surely this would work out cheaper than buying the retail version.
In any case you should really NTFS format the hard disk before installing
Win XP rather than continue using the FAT32 filing system. So a clean
install would be better all round. In the meantime save your user files onto
CDs or DVDs to drag and drop later onto your NTFS formatted HD.
I've been following the advice given on NGs and the above would, in my
opinion, be the best solution for you. It has certainly worked for me. And
I've had no hassle even when installing some drivers which were not strictly
for XP. Judging by what I have seen on NGs, people who have had hassles have
been those who have failed to do a clean install. Anyway, NTFS formatting is
what is supposed to give Win XP better stability over previous systems.
You might not be able to use the Upgrade Version of Win XP anyway if you
haven't got a qualifying Windows CD unless you don't care for a clean
install which I for one would certainly NOT approve. However, if you do
decide on an OEM version do NOT go for the branded (i.e. DELL or the HP)
versions but the standard unbranded OEM version.