My computer fell ill

The computer could not start, appeared as follows:Reboot and select proper Boot device or Insert Boot Media in selected Boot device and press a key.
Ask that what meaning this is? What question is my computer? Question supplement:How do I solve Arab League?

Starts and chooses the starting outfit or the insertion startup disk and chooses the starting outfit and presses the random key The insertion startup disk and chooses the starting outfit and presses the random key