My pc will not bootup when switched at mains

Try this link, looks like you need to repair boot:
http://h30434.www3.hp.com/t5/Notebook-Lockups-Freezes-Hangs/HP-G72-b66US-Notebook-PC-Dosn-t-Boot-into-Windows/m-p/1336579#M22150

Power off the machine. Pres the power button and immediately start tapping F2 until the machine goes into the BIOS menu.

This seems to be a common problem. Plug in the mains lead and try to boot up then. Come back and let me know please.

Reprogram the door opener.

No power and power LED does not light up, this indicates either the mains power is off or you have a faulty power lead. Test the mains socket and the mains power lead.
If these are OK then the fault most likely a faulty switch mode power supply. Remove the switch mode power supply and get it tested at your friendly computer repair shop OR borrow a power supply and insert it into your PC to see if it now boots up.
If it boots up the replace the power supply with a new switch mode power supply with the same total wattage or higher wattage.

you have a chip problem that will need to be re soldered,try pressing down hard beside the insert button as you turn on your computer and see if it will boot.

reboot ur cpu,,as soon as u see the hp screen start pushing esc key,,come up to a boot menu,,make sure ur main hdd is number 1,,if that dont do it ,,,system restore,,

The main light flashing 10 times is the sign of a door sensor problem. Check to see if the small light on each sensors is lit and not flickering. If you cannot get both lights to come on your sensors or the wiring to them is bad.

have exactly the same problem, and same laptop, what operating system do you use, becuse my problems started after i changed to windows 7, had my one for 20 months as well more or less

press hard disk and boot the windows