Notebook doesn't start

[Willemvanwaas]

Hi,

My laptop suddenly fails to start. It does charge (the charging light turns on when I plug it in) and it does the same with or without battery:

When I press on, it seems to start. Three of the four lights (not the power light) at the front come on, and the keyboard flashes white, as well as the power button. However, after about 0.5-1 second, it stops, and the power light flashes four colors (white-yellow-white-yellow I think), until it all stops and starts over after about five seconds.

I tried charging it for a while, didn't work. Nothing happened recently to it that could've caused this, that I know of.

Thanks in advance!

Willem