Windows XP unable to see files on CD

Hi

I have a client who uses Windows XP to write file to CD. When they have finished the writing process these files cannot be seen on the CD, although, if they move the CD to another machine they are visible. Also, if you insert a CD that has been written you cannot see these files either. However, in the past (about 2 months ago) I have installed programs from CD previously using written CDs.

This PC uses a DVD+/-RW to write files to CD using Windows CD burner. Although, I have installed Nero to enable the machine to write to DVDs.

Any ideas?