PC won't start after new cpu

[Minymigitover9000]

So a while back I decided to buy the gigabyte r9 270x OC and an i5 4430 as an upgrade from pentium and gt 630 to start gaming again. I go the new GPU plugged it in and the PC worked properly(with my cx600 psu). Then I got the CPU and plugged it in, fans turned on for a second then everything stopped. Then dicided to put the old CPU back in and it did the same thing. The only time it doesn't do it is when I dont a have a CPU in.

 

[norsestar]

Try clearing CMOS. What make and model of motherboard do you have and which BIOS version?