HP DV7 No boot

Last week my HP Pavilion DV7 3079wm overheated because my cousin left it powered up on my couch for at least 5-6 hours. When I got home and attempted to use it the laptop shut down and I attempted to power it back up when the screen was showing all sorts of lines then it shut down again and all that it would do there on after was light up then back off, no fan or anything just the LED's for the power and volume etc.

I figured the motherboard was gone or something along the lines of the graphics so I purchased a new motherboard and installed it and when put back together it does the exact same thing it just lights up the LED's then they shut off. I put new RAM new and that didn't change anything so does that mean my CPU is gone?