So I partitioned my MacBook's hard-drive so I could put Windows 7 on, using BootCamp. That all went well, except for some reason, the Windows 7 wouldn't work on the partition, according to the installation program. So I thought "Oh well, I already have Vista and XP on Parallels." I returned to OS X, and went to Disk Utility. I erased the partition I created, and when I tried to resize the original partition afterwards (so it took up the whole hard-drive again), it... failed. The computer froze. I held down the power button for several seconds, and then it shut off. When I tried turning it on again, the computer said "No bootable device found. Insert bootable drive and press any key." (Just for giggles: imagine a 16-year-old kid who paid $1600 to get a computer in this situation. Yeah, that's me.) After I calmed down from my panic attack, I restarted it again and held down the option key. Thankfully, it gave me the option of starting in "Macintosh HD." Everything fixed... right? Wrong. I was on the MacRumors forums when my computer froze (stupid "grey screen," and it makes your music skip over and over which is really annoying). When I shut it off and turned it on again, once again it gave the same warning about a bootable device! What do I have to do to make it so the HD is the bootable device?