Dell Inspiron Keyboard Problem

Hello,
My keyboard not working. Initially I could restart the computer, open word and internet email and google. When I type the computer would only display 2 of the typed letters and then stop showing the rest of the typed text. To resolved this I switched off the computer 2 times but the problem persisted. The 3rd time I switcehed it on it is showing a page (black with the tittle,Windows boot manager
The instructions are that I must choose an operaating system to start or press TAB to select a tool. When I presss enter, Tab or ESc the computer is not responding at all. How can I solve the problem. How do I work on this?