PS2 discs not readable in CD drive

[rosst]

I may be being stupid here, but I just put a modchip in my PS2 and bought a Freecom Classic CDRW. When I put a PS2 game disc in the CD drive on my PC to copy, the computer cannot read the disc. I tried on another PC and all I get is 'please insert a disc in drive d:'. I've tried two different PS2 discs. What am I doing wrong?!?

At the moment I cant even copy the contents of the PS2 disc to my hard drive to patch!!

Thanks for any help you can offer!!