John - I am very aware that one of the first steps with an old backup is to get the Antivirus protection up and running (with current rather than obsolete virus definitions).
I am also aware that a working firewall will stop other nasties getting through.
I am also aware that anything which leaps unsolicited off a web page at me and says "Trust me, I'm your friend. I'll look after you" is likely to be as trustworthy as the snake who sold Adam the apple.

I can't recall where my copy of XP falls relative to the official Service Pack updates. I expect I will have to restore the copy and then see what patches are needed. At least we have broadband, so downloading CD quantities of data isn't as much of a problem. It still takes a long time to install Microsoft patches, but a lot of that is because it insists you reboot your computer between every patch.
At least once the process has been updated to April 07, I would then be able to back up (using Acronis True Image) the clean system at that point in time, before installing new software.

Quack!
GtD.