When it does boot, have you tried downloading "System Update" by Lenovo and run any driver/bios updates? bios update i suspect could be the most helpful here. Does it only have 1 stick of RAM? If there is 2 sticks, you could always take one out and see if it works better without 1 of them. I think it's less likely the RAM if it works well after the PC does boot. What about only shutting it down when absolutely necessary? Set the laptop to never sleep, etc. Hope this helps.. definitely seems like the MB could be prime suspect.