Hey Tim, I'm also Tim and will be assisting you. The motherboard bay have some small LEDs that are lighting up to show a problem, but the problem with a bad motherboard is, those lights may not work. The two things that blow on a power surge, or lighting strike are generally the power supply, or the motherboard. Best way to test for motherboard, is with another motherboard.
does the harddrive start spinning? assuming its not an ssdi?
ok, so no way to see if its running. Fans on video card are on, correct? DVD/CD drive open?
You can always try resetting the cmos battery (remove it and put it back in), doubt that will do anything.
since this is a HP, you can't just run out and grab a motherboard for it as if it were a home built PC, so thats kind of rough, however, saddly the problem probably lies in the motherboard.
Tim, are you still with me?