Computer Caution comes without operating system. I have not used the EFI system, but the good old BIOS (legacy) with a dual boot Linux Mint 17 and Windows 8.1. In the case of Linux no installation problem, problem-free market except the sound that can only be changed in KMix. This is a minor and I did not yet discussed the resolution For Windows 8.1, the installation went smoothly but when the restart is lost internet and screen resolution. Using the Drivers CD have emerged, but this lengthy installation solved the problems. In 2 cases, the webcam appears as unrecognized ... it must be activated on the keyboard with Fn + F6. The backlit keyboard is convenient. The upgrade of the RAM and the addition of an SSD involves the cancellation of the guarantee. Not cool knowing that it is a selling point.