How can I tell there are pictures on my CD?

On a Mac or a PC?

Insert Cd, allow it to mount and look at the files on it…...
Without more info I can’t give a more eloborate answer.

grooves? you sure they aren’t deep scratches?
if that’s the case and it is scratched up, the common way to fix that is take some chapstick, and rub it on a cd, then lightly wipe off the excess.

i’m not 100% sure what you mean, but hope that helps.

Can I retrive old picture’s off a diginal camera disk if taken off?

hold it to the sun during high noon. It will cast a shadow of your pictures behind you. Or you can just load it in the computer and wait about 30 seconds for it to load. Either or.

What do you mean by digital camera “disk”?
if you mean SD card, maybe, depends on the circumstances, you can sometimes recover any type of file; trying using a file recovery tool and you may be able to, but you still aren’t making to much sense.

Trying a recovery tool is the best advice I can give you.