Well here’s the update.
I posted my original query from my office PC yesterday. My home PC had been going slower and slower over the last few weeks, and my wife called me to say that it was freezing during startup.
My plan was to go home last night and tackle the problem using the boot up disc. However, no amount of coaxing would get it through the startup phase. I have very limited computer knowledge, but it seemed to me that it was trying to run a lot more start up programs than usual. When I pressed control alt delete I saw names of programs that I simply didn’t recognise, and there were quite a lot of them.
In the end I had to surrender and reinstall Windows, and while I was at it, I reinstalled Microsoft Office 2000.
The PC is functioning a lot sharper now. I have temporarily lost my broadband cable Internet access, so I am using dial up today (I’m expecting setup discs in the mail next week).
My guess is that the problem was caused by some sort of virus (although I use grisoft AVG which updates every day and it gave me no alert messages).
Fortunately I didn’t lose any documents or even Internet favorites.
Thanks again for all the resources recommended.
Dave