I can run the knoppix cd (V 5.1)on my hp laptop fine. It will boot and do everything I try. I downloaded and burned at the slowest Nero speed (4x) I could. MDA checksum is OK. When I try to run it on Sony VAIO desktop, it locks up. It boots up and I can open or start to open some of the programs. Then it locks. I can move the cursor but there is no response by the OS. The only thing I can do then is to turn power off to reboot. Can there be a problem with the CD-Rom drive or CD-RW drive? Is there any way to test the drives to rule out that possiblity?