Hej. Yesterday, suddenly my Macbook air´s keyboard and the touchpad started not to react. I didn´t do anything, just let my laptop on the tabel for 5 min. and when I came back, it wasn´t working and when I really don´t know why, byt sometimes, when i shut and start it up again, it starts working for some min/hours. Do you guys have any idea w hat the problem can be?

SOURCE: macbook pro start up problem

First remove the battery, then plug it into your AC adapter. Hold the power button for 5 seconds or until you either hear and beep or the activity light on the front of your laptop lights up. Start up normally. 

SOURCE: MacBook laptop 3.1 keyboard issue, Leopard OSX

I too have had Macs for years.  The one you have now I also have.  I have had no problems with it yet.  Whenever I have a problem I just take it to an apple store and the Genious will either fix it or be able to tell you what is wrong.  It doesn't matter if the warranty is valid or not, they will take care of the problem for you.
Sorry I have no other help for you.
fullard

SOURCE: ibook G 4/12.1/1.33/5aptx.....will not start

Some computer react this way when the logic board goes bad or have a defect in it.  
First, Try this:  
Remove the battery.  Plug back in the power cord, then press and hold down the power button til you hear a loud beep sound. then release it.  If the computer starts back up... Then you should be okay.
If not, it may has something to do with the logic board.
Let me know if the above works... We may can try some other things if not.
~ enov8

SOURCE: MacBook startup problem

To get a disk out of a mac hold the mouse button down whist the the machine is booting up and it should eject automatically.
WIngammon, try this.
hold Command - option P R straight after you turn your mac on. This will reset the PRAM and NVRAM. this might help.
otherwise if you have an original or copied osx install disc try booting up from that by turning on your computer, inserting the disc and then turning it off again. Give it 5-10 secs and then boot up again holding the C key. this should take you a screen similar to the login screen, you will have to choose a language. In the toolbar(top of the screen) you should go to utilities and select disc repair.
I have had this problem with my own macbook and the above things have solved it for me. However its possible that the same symptom my not be caused my the same problem.
Best of luck.
Let me know how it goes.

SOURCE: MacBook Air Sound Problem - Same Situation

this is due to accidental disconnection of wire internaly so go to an authorised dealer and repair it otherwise it can also harm to your logic board if it touch with that rate it plz