I have back-up CDs that I made with a computer using XP. I am now using a computer which uses Vista. The newer computer does not recognize some of the older CDs although I can open them on the XP computer. Why would this be?

   That all depends on what you used to make the CDs, what format the backup files are in, and whether Vista supports that format.  Our backup program, WinRescue, makes the backup files in ZIP format which is supported in all Windows versions.

Can the CDs be converted to different formats?

What format are they in?  What did you use to make the backup CDs?

I don't know the format. However, I read the CDs in question onto my XP machine, then copied them to a different CD. The new CD is readable on my XP machine.