HL-DT-ST CDROM - won't play one CDROM - help!

Dear Group,

I have a Compaq PC clone running Windows 2000 with an HL-DT-ST CDROM model
GCR-8408B. I have had no problems with it - plays CDRs and audio CDs.

As birthday present for my son, have bought (second hand) 'Battle For
Middle Earth' CD Rom, in original box - not a copy. (In fact, I have two
identical boxed sets - by mistake...)

My drive will not recognise either CDR. I have tried them in another
machines CDR which recognised each of them as the Lord of the Rings CDR. My
drive whirrs and chugs for a minute before asking for a disc to be inserted.

Any advice welcome.

TIA