What pattern are they blinking in? Is it a constant equal blinking or does it look like its a 2 blink, break, 4 blink, break 4 blink ect? Those are the diagnostic codes. Similar to how BIOS beeps work. But a few things to check is that the CPU is is seated and locked down properly (The screw on the socket that you turn to lock and unlock the CPU to remove it) check and make sure Ram is seating properly, and make sure other things are also connect properly. Just double check your work. I always try to test the laptop before buttoning it all back up.
Thank you for your suggestion - I rechecked all connections, the CPU was not locked properly - now it works fine