If it can recongnise a CD-R and not a CD-RW you will need to get a new cd-rom drive.
Basically it is because a CD has a highly reflective silver surface whereas a CD-R only reflects about 40-60% of the light (laser) and a CD-RW is something like 20-30%.
Older cd-roms that weren't built for CD-R(W)s in mind aren't sensitive enough to "see" the reflected laser beam, so they assume there is no CD in the drive.
Hope this helps
