New motherboard now over wont work

Just upgraded my motherboard and now my PC won't turn on any help would be nice I want to get it fixed before the summer sale ends 

define won't work? does it not post, does it not power on, even a litle bit then stops, do fans and HDD move?

have you made sure...

  1. the 24 pin is in and all the way
  2. the 4/8 CPU power pin is in and all the way in
  3. the 6/8 pin PCI-E power cable is plugged all the way in
  4. the PSU side modular connectors are plugged in and all the way in
  5. the power cable is plugged in the back and into the wall
  6. the PSU power switch is on
  7. your bios supports you CPU i,e older z68 boards need a bios update to support ivy bridge CPUs
  8. tried each ram slot individually
  9. tried each PCI/E slot individually
  10. reset the bios

Very nice list.  However, to add to it.  Some motherboards have an LED debugger on it, pull the code off of it and post it here / google it.  

more details op. - board? cpu? ram etc.

old 1155 board and ivy cpu may need a bios update etc...

there are so many reasons why it wont boot

> most likely some silly error when you were putting it together so check everything in that list above

> make sure that the motherboard standoffs are in the right spot and stray ones arent making contact with the board - this will create a short and dead motherboards... lol seen it happen many a time

> when you put the cpu in (intel cpus mainly) pins were bent or the cpu is inserted the wrong way (i dont know how have physically saw this on customers board. facepalm..)

> post some photos for us to look at if you are unsure.

> you put a pcie cable in where the 4/8pin cable goes.