how to copy only modified files from disc

I am transferring files from my destop pc to my laptop. I
burned a backup fo my excel, word and image files to a cd-
rw. I have copied those files to my laptop drive from the
cd. I am now tring to update the files and would like to
save time by only copying new and modified files to the
laptop drive. My roxio burner allows me toonly copy the
newly modified files from my desktop pc to the cd-rw. I
would like to only transfer the new files from the cd-rw
to my laptop. Is there an easy way to do this?
Thanks