Are you logged on as Administrator, while attempting setup?
Anyway, I found this forum thread that might help (with links):
http://social.msdn.microsoft.com/Forums/en-US/vssetup/thread/8655d21b...
Shorter link:
http://tinyurl.com/yk6dfts
Thanks for the double tip, Iceman. I think it's because I haven't yet
activated XP from the last "wipe-out", so that's the next problem. I
have re-installed XP Home ED & never had an activation problem till
now. The ID numbers (9x6 groups) seemingly are causing grief during
activation IE; "fault with your *********numbers"
I have spoken "live" to the call centre & been given a telephone (UK)
number to call..tomorrow as they are closed weekends. Have you any
idea why NOW I am having problems with activation. I have a genuine XP
cd bought at the electronics shop where I bought the parts for my PC
(self-built) and never had any trouble before now. Thanks for your
prompt reply.