Okay, I've found my solution and I am a bit red faced here.
It seems that, some time ago, I did back up a complete, separate, second WinXP installation to VirtualBox. I can't remember when I did this, but I had a copy of it on my storage drive.
(For some reason, the area of this storage drive is only accessible as root...not sure how that happened. No matter, I just used Konqueror Super User Mode).
I simply moved the VDI over (and changed permission to user) and added it. then, I added the machine and I'm up and running!:)now I can install this piece of Windows software and mess around with it to my heart's content without worrying aobut messing up my main WinXP installation.
And, the nice thing is, I have both WinXP configurations backed up on the storage drive.
My sincere thanks to everyone for their input and help.
It certainly helped me to avoid making major mistakes.