I had a similar one recently on a Compaq laptop, owner managed to knock the power jack on the edge of a chair and broke it. I found an identical power jack socket inside a dead scanner in my junk pile, a bit of dismantling and a dab with the old soldering iron and it was running again. Compaq's official cure for this problem is a replacement mainboard at ludicrous expense. I could have bought a power jack socket for peanuts at Maplins (Brit equivalent of Radio Shack) if I didn't have one handy.