not even the bios came on. nothing. flatline. to me that says, fried mobo. that thing is dead mate. if i were you, i'd get a new mobo and see if the other parts are still working. and if you can't determine that, or do it easily, then ask a professional to test the processor and the graphics chip and other parts. if they still work, you can save some money and just get a new mobo hopefully. otherwise...you're kinda screwed.
by the way...if you can, try to avoid hp. they are seriously going down in terms of quality and warranty support. gateway, lenovo, acer, and a few other brands are now the way to go.
but that's a side note...yeah...get a new motherboard first. sorry about that...not exactly a very pleasant thing to have happen to you, let alone to have someone tell you what you feared most....i wish you the best.