10.4.11 Intel 2GB MB This is the 2nd $29 SL disc that won't load on my MB. I returned the previous disc for this disc and am getting the same issue. MB tries to read the disc then spits out the disc after about 20 seconds. No message shows up on the screen or anything. Not a disc drive issue since other CDs work fine. Were both discs defective or is there some other issue? Haven't others been able to upgrade directly from Tiger to SL?