Just bought an 811S and put it in external FW/USB 2 casing. Drive works fine. But when I have both the 811 and the 166 turned on, the computer hangs on startup. I have to switch one of them off. Any ideas as to why this is happening? They both work fine on their own when only one is on before startup. After startup, I can switch on the other with no problems. I previously had a Pioneer 106 which was replaced by the LiteOn 811. At that time I had no problems with startups.