Whilst my computer was turned on, I shut the lid down and I popped out. When I came back and opened the lid I now can't get it to restart - I pressed the 'enter' key, the power key but it won't start up. The power light is on and so is the battery light and another light.

Remove the power connector and the battery. Press and hold the power button for 10 seconds. Plug in the power but leave the battery out. See if it will turn on. If yes, once it's fully booted, do a normal shutdown then install the battery and power on again.

It worked !!!! Thanks very much.

You're welcome. Thanks for letting me know.