Daughter was using my machine on mains power with no battery connected. Power lead came disconnected then reconnected straight way.
Status now is:
On pressing on/off button there is a slight whir from HDD which stops immediately, Power indicator comes on, few other lamps flicker on then off, then Num Lock stays on and thats it! Machine is totally quiet.
On/off switch will not switch machine off. Can only switch off by removing the battery. Cannot access anything using F2
Have removed HDD same result.
It's still under warranty but wondered if it's anything obvious.