If these two statements are true:
- your wife's computer runs XP, and the same versions/configurations of Nortons, Acronis, and Calibre
- you can add books to a calibre library on your wife's computer?
Then the cause of the problem on your computer is probably NOT related to Nortons or Acronis - but something else that runs at startup on your computer but not on your wife's computer.
Piriform's CCleaner has utility tool that provides a user friendly UI for managing taskup tasks, I would use it to see what I had, and use its disable/enable feature to isolate the problem - you'll need to do restarts but on XP especially that should easier than going in and out of Safe Mode. Get the Free version See ==>>
https://www.ccleaner.com
BR