Hi, I'm in the process of erasing my old imac so it can have it's HDD replaced by apple under the recall. Normally I would insert the original disk, boot from it and erase the HDD. Now it won't boot from the DVD. It just spits it out or displays it with a white circle crossed out over it. This is the original disk. I am now trying a generic retail SL disk but it's been stuck on the apple logo for about 10 minutes. ML internet recovery doesn't let me use disk utility either. Can anyone offer any suggestions? Thanks.