NZFF

Well my laptop my have carked it...?
I was about to start a flight to Sligo from Dublin on FS9. I went away for a short tick and when I came back it had frozen. There was sound but the keyboard and mouse weren't responding at all.
I used the power button to turn it off, holding the button down. When I tried to turn it back on it would turn on for about 3s then shut off (with the same noise it makes when you hold the off switch and it cuts the power to itself etc..) and it would keep repeating this cycle non-stop.
I was plugged in the whole time so i tried with the battery then I tried with the battery removed.

I then tried the battery out, unplugged from the wall, hold power button for 15s to reset trick but with no avail.
Any ideas with what's wrong?

Are there an unusual amount of beeps when it tries to start? Sometimes the number of beeps can help indicate what area the fault is in. Now I have no idea if this is still a valid method or if it even applies to your case.
Also, can you try booting from a windows (or other boot capable disk)? See if that works maybe, then you can get in there and have a look and see what is working or not. Could be your HDD and if you boot up with a disk you may be able to see if your HDD is indeed fubar.
Just a couple ideas from a tech noob.
90% of the people here know about a million times more then I ever will so will have a better understanding and be better able to suggest ideas.

Well maybe on startup you could press F8 then from there its pretty straight forward, infact that has happened to me too, i went and replaced all of the texture files with the VOZ 1.8 ones and it just froze when i fired up FS9, maybe this is your problem, what was the latest add-on you installed? remove it and see if it works fine.
Cheers.

I had something like this happen last year. Gave up in disgust and left it unplugged, with no battery. A couple of days later I plugged it in again to see what would happen and everything worked just fine. Why? No idea? I had already tried everything that you did so maybe you could try the same - unplug the battery and the power supply and wait some undetermined long time and then try the restart - you might be lucky like me.