The mostly reason is Ivy Bridge CPU cannot be supported by BIOS. Please follow the below steps to support it.
1. Turn on the PC with Sandy Bridge CPU like i5-2xxx.
2. Follow the POST prompt to press “Del’ key or other key enter CMOS, then check ME FW version is 7.0.x.xxxx or 8.0.x.xxxx, 7.0.x.xxxx cannot support Ivy Bridge CPU, it must update to 8.0.x.xxxx.
3. Refer to here to update BIOS with ME FW 8.0.x.xxxx.
4. After flashing BIOS, turn off the PC, and then install your Ivy Bridge CPU to make the PC display.
--ME FW version 7.0.x.xxxx.
--ME FW version 8.0.x.xxxx.