Thanks, Adamsappleone.
I have discovered a procedure at XP installation for adding "missing" files (drivers, in the case referred to) to the XP upgrade at:
http://209.167.114.38/support/techsu...-TSB001272.htm
My guess that I will be able to use this procedure to "patch in" the mfc42.dll, setupapi.dll and cfgmgr32.dll files a copy of which which I can take from my XPProSP3 desktop. I am assuming they are simply copied into C:\WINDOWS\setup\ along with the other files from D:\I386\
That requires me to connect a floppy disk drive to the laptop which the Toshiba laptop fortunately has. All that is missing is a spare floppy disk to use - they are not that easy to come by these days out here on the edge of civilisation (New Zealand)!
Please note that I have followed all the procedures recommended by Microsoft for "minimising" the system prior to an XP Upgrade (except the manual compatibility check as the references are not longer available - the links in the Microsoft documentation now go to the Microsoft Vista upgrade site!). I have ruthlessly deleted applications and, as mentioned above, have a clean Windows XP Upgrade Advisor report. Even dropped the mouse for the ghastly Toshiba toggle pointing device.
I would appreciate your comments (and best wishes, if appropriate) on what I am suggesting before go ahead and attempt the "patch in" upgrade.
Regards
Peter
PS There are references to this specific problem in support sites across the internet (including Microsoft, Toshiba and the suppliers of the installation CD/downloads) and not one appears to have a definite solution. The problem, i.e. upgrading from a previous Microsoft OS to a newer one with service packs is, I feel, more likely to increase than go away.