Old CD's from XP is not working in Win 7

Why is the CD I have created in my old XP not working in the new Win 7 .
Same hardware and PC as before.

How was the disc burned....what program was used?

I used XP file manager and burne from there.

That could be the issue. The built-in app, especially from XP wasn't very reliable, and caused many issues like this. You might want to virtualize a copy of XP just to get the contents off those discs, and then burn using something better, like CDBurnerXP or ImgBurn.