You deleted everything from your USB key or a drive, so there should be enough free space to copy the new files, but you still get the not enough free space message in Mac OS X? This is what you need to do.
If you experience an Mac OS X program to freeze and you cannot exit it by clicking quit or using a keyboard shortcut, you can always force it to quit using the Activity Monitor.
If you find yourself in a situation when you need to list your Mac specs or you just want know if you really got what you paid for, this is how you find them out.
You can add multiple desktops to the Mac OS X Mountain Lion by using Mission Control, formerly known as Spaces. Can be really useful if you are a busy multi-tasker.
Mac OS X Moutain Lion and its Safari web browser sharing options allow you to share and send any web page vie email as a PDF attachment in a matter of two clicks.
Without too much fuss, Apple released a new version of its OS X operating systems for Mac computers. The great thing about it is, that it's completely free for the existing Mac OS X users.