Lenovo z510 does not start. No fan and display or bios.

Hello, month ago i shorted my motherboard and bought a new one. So i put it in my system everything went normal first 5 days, and once my display freezed white colored amd laptop completely shuts down in 3-5 seconds. Later i could not turn it on even if it charged battery and i had all the indicators. Fan did not begin as well. I reseated rams, no result. And went to sleep very sad. But in the morning i pushed button and it booted as nothing happened, i used it like 7 hours and it again freezed the same way, white and shifted picture display symptomes and it did not boot again . So i waited 5 hours and it boot up again. But very soon freezed again. What can be the problem? Please help me