It doesn't work with a new BIOS battery either, although the old one was a little flat.
Symptoms: It powers on the fan and the wi-fi light. The power light is solid. The battery light changes from white to amber (charging) when you plug in the power supply. The optical drive 'chugs' as it turns on.
The screen does nothing. There is no option to enter BIOS. The Caps Lock light will not come on. The HDD light dosen't come on. There is power to the USB sockets but I cannot boot from them.
There has been no odd behaviour from the laptop. It is dual boot Windows/Ubuntu and has not been crashing or behaving erratically. The only slight oddity was some trial software we had on Windows - the 'days remaining' went from 30 to 29 and then never changed again, but I assumed this was a software glitch (and didn't investigate obviously!) Perhaps this indicates an issue with the BIOS clock?
I've tried:
Booting with no HDD
Booting with no RAM
Re-sitting RAM
Booting with no CMOS battery
Booting with a new CMOS battery
Removing battery and holding power button for 60 seconds
Booting with no battery
Booting from USB
And I still have the same thing - a laptop with the fan on, the power light on, the charging light on and the wi-fi light on, but nothing else.
It looks like a falure of something critical, but the odd thing is that it wasn't even beong touched when it failed. It was in a room with nobody in attendance. It had been re-booted since last being used (I shut down before bringing it home from work) and was absolutely fine - I'd used it for web browsing and playing music that evening with no issue, and left it playing music when I went into the other room - and at some point after that it failed, when no-one was touching it or moving it. Does that sound likely? I can't think what else to try.