Win98 - thanks for response.
Yes, I use Win.98se and Win.XP, both installed, but I installed Win.98 first.
There's a heap of info on the WWW about how to install an older OS over XP. As you will know the older OS will overwrite the XP Master Boot Record which has to be recreated by doing a Repair Install or by using FIXMBR from the the Recovery Console. But beware, if you want to use the Recovery Console there is the chance that you will get into an endless loop being asked to enter your password, even if no password exists, when setting up the RC. There is a Registry Edit to sort this out which should be applied before attempting to start the RC.
Here's a little from the WWW.
I have never retro installed an OS and my best advice is to backup, backup and backup again before trying it.
Anyone care to comment on my query about installing programs please :-?