The Pletor drive that you have should read the disc in about 8 minutes, not 10-15, so this leads to be a driver issue or a system issue. I would try to get the very latest drivers for your USB 2.0 card that you have in the computer. Also try upgrading the Firmware for your Plextor drive at:
http://www.plextor.com/english/suppo...firm_2410.html
If you tell me what brand of USB 2.0 card you have, I will try to find the latest drivers for you.