Just an FYI: This is EXACTLY what happened to my DV9700 when it died. No lights, no nothing. The circumstances were slightly different, but the behavior is identical.
I would venture a guess that your motherboard is toast. I don't know what video card you have, but there was a batch of bad nVidia cards (8400-8600 series as I recall) a few years ago, and they liked to die when the solder gave out during cool-downs and warm-ups brought on by computers going to sleep and waking up/powering on.
For the record, money is obviously not an easy thing to part with, but just a quick look on my favorite board replacement site reveals three models for the DV5000 series with a maximum of $50 for the most expensive one. *Edit: There is also a DV5100 series with a slightly different set of boards, you might check both* It would depend on which model you have (the label is typically under or around the RAM slots on the board,in format xxxxxx-xxx, that's "6 digits"-"3 digits") and how adventurous you feel in disassembling it. For that, search your model on HP's website and look in the manual section for the maintenance manual.
The shop site, if you want it, is: http://www.getpartsonline.com/
*Edit 2: You can search the exact model number on the left part of the page in the search line, just type your model number and click the "Go" button. If they carry your model, it will show in the results*
Hopefully that helps you out some. Not great news I realize, but hopefully the lowish prices give you some relief at least.
O Shadow Fox O