A strange PLL problem

I get a strange problem!

I use the stratix II GX with my design .It ran properly two days ago. I put my design board to a new environment the day before yesterday.It ran porperly in the first two hours.However it didn't work suddenly.The new environment is a place Bad earth.My porblerm is all the Pll in stratix II GX did not work,so the logic which drived by the pll

did not work ,and the logic which drived by the input pin clock ran properly.

the pll is broken ?

Is there any way to solve the problem?Thank you!

my email is :zsan566@163.com