No Sleep is a Mac OS X kernel extension designed to prevent your MacBook from going to sleep when you close the lid.
No Sleep project consists of kext and userspace tools that help you manage sleep behavior.
No Sleep package contains the kernel extension which will be preventing your computer from sleep, and a preference pane plug-in to facilitate managing of extension behavior. nosleep.kext will be installed to /System/Library/Extensions
nosleep-preferences.prefPane will be installed to /System/Library/PreferencePanes
To permanently disable extension you can just remove these files and restart your computer.