A blinking red light near the CPU on the motherboard can indicate 2 things.  1st it can indicate the CPU is overheating.  If you are able to load into windows, you can check the CPU temperature using the E-Leet tool.  If windows cannot be loaded you can check in the hardware monitor in the bios.  The temperature should be no higher then 80c. 

If the CPU does not appear to be overheated then it could be detecting faulty power.  Please check to make sure the 8 pin CPU power connecter is conected.  If it is connected please reseat the cable and test again.

Last it could be a faulty or improperly mounted CPU.  Test the board with another CPU and also verify there are no bent pins in the CPU socket.