When we replace motherboard and screen, we only give 30 days warranty on parts. After 30 days, if your motherboard or screen does not work, we can not gurantee because all vendor we purchae those parts only give us 30 days warranty. However we will give 90 days labor warranty. If we find out customer trying to fix themselves by opening back cover of laptop, we do not give any warranty. If you have any questions or concerns, please give us a call at 712-256-8686 or 402-502-7040.