I installed Mountain Lion on my mac and also installed it on my daughter's Macbook using my Apple ID, not realising we would then be sharing bookmarks, etc. Can I now install Mountain Lion again onto her computer using her own Apple ID?

Thank you so so much. I unchecked Safari in my icloud and it seems we now have separate bookmarks again. (She deleted dozens of my bookmarks earlier thinking she was only deleting from her own Mac. I've managed to restore many of them but not organised as they were with my own notes on them! It'll take many weeks to sort out.) I also tried unchecking Calendars in icloud as our calendars have merged, but it tells me my calendar will be deleted from my Mac.

Still wondering if I should just install her own Mountain Lion on her Macbook with her own Apple ID (what I should have done in the first place probably) or will this cause issues with installing one mountain lion over another do you think?

Thanks Barney-15E. Went to her Macbook to log out of icloud so she can login with her apple ID. The first message that came up was that all calendars would be lost so we backed those up on each Mac. The next message said that all documents will be deleted if we log out of icloud on her Macbook. After losing all my bookmarks we're a bit nervous about losing more stuff. Does this mean material will be deleted from her Mac as well as mine is she logs out of icloud do you think?

Problem is we don't want to lose anything. Because we've only just set all this up, icloud storage is showing that 4.99GB of 5GB is available so wouldn't bother me if we lost what was in icloud. Just don't want to lose anything on either Mac.