Hello, MacRumor(ers?) This is my first post here and I just have a quick question. My DVD burner on my Macbook Pro 15 is not working correctly, and I just want to know if it's possible to upgrade my Mac from 10.7.5 to 10.8.x just from the InstallESD.dmg file. Or do I have to actually go out and buy a flash drive? (I've been googling, but can't find a straight answer yet) If I can just upgrade from my desktop, that'd be sweet. I'm new to Macs, but expect to dive deep into this fantastic land. So far, I'm liking it a lot! If I can do the upgrade with just a disc image and without a DVD or flash drive, please do let me know. Thanks a lot!