HP G62 Will Not Boot With Power Cord Plugged In

I have an HP G62 laptop that is about four years old. I've had a couple of problems with it before that were resolved relatively satisfactorily, however five or six months ago I started having a new issue. The laptop will not boot with the charging cord plugged in, whether there is a battery in it or not. Nor will it return from sleep mode (screen black, status light on the power button flashing) with the charging cord plugged in, whether there is a battery in it or not. It simply shuts down and I end up with an error screen the next time I boot up. I have tried other charging cords and it has been the same, however the cord will still charge the battery. This means I have to charge the battery, unplug the cord, boot up the computer. This annoyance is worsened by the fact that the battery is old and unable to hold charge for very long at all and I fear one day even the battery won't be enough to boot the computer. Can I fix the power cord issue? Should I buy a new battery? Or let my computer give up the ghost and scrounge for a new one? Any help would be greatly appreciated.

 

Sounds like there is something not working on the main board and that is why it isn't booting up or waking up, in my opinion, it's likely that the computer will die out completely eventually. 4 years is pretty respectable for a consumer unit, so personally, I'd start planning my next upgrade.

 

Yeah its extremely respectable for a budget consumer unit...