I have an August '07 iMac (27inch). Today, it started acting up very badly, and wouldn't load up properly at all. Things just kept getting worse and worse, so I finally threw in the towel. Deciding that I didn't have anything on it I wouldn't miss or couldn't just re-install, I figured I'd reformat it and start fresh. Well, that seems not to have worked. I attempted to erase the existing hard drive through the disk utility, but it informed me that it couldn't. However, upon restarting the computer, the hard drive no longer appears in the disk utility. I also cannot install Mac OS X 10.7 onto the computer as it can't find any disk to install it on. Everything I try seems to make things worse. Have I managed to be one of the few individuals who knows just enough to actually screw up a Mac? I just want to be able to use my computer. On a mildly related note, is it possible to just install Windows 7 on an iMac without OS X working? I'm not sure, but given my bad luck so far, I don't want to push my luck.