Please Help ASAP-Installed new MB fine/ Now won't power up at all

[jamesrwright]

I installed a motherboard yesterday-LGA 1156-i5-750. I bought a better case fan and installed that today. I tried to turn it on-light turns on for a second then shuts back off. It keeps rebooting itself-it turns on less than a second and does that over and over again. I reintalled te old case fan and no cigars.
What is wrong?What would case that? Any ideas?

 

[o1die]

Sounds like you need to do a bare post to rule out a grounding issue with the case. You may have something touching the board under or around the case area. I use a phonebook, and take out the power supply if needed for the cables to reach. You don't need to use the optical or hardrives to post.

 

[jsc]

Our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems

Having said that, breadboardind is a good idea. It will eliminate case problems:
http://www.tomshardware.com/forum/262730-31-breadboarding

 

[jamesrwright]

Still clueless why it all of a sudden stopped working. It was up and running fine..then i go to change the case fan to get better cooling..install it..and it didn't work-changed the case fan to the old one..did not work..

I installed my old AM2 board tonight and the system is up and running fine..so it can't be any of my components..PSU, Hard Drive..ETC..maybe bad motherboard?