Try re-seating your memory. Also, when you are doing this, remove the memory and turn the laptop on to see if it beeps. If it does, then simply put the memory back in, after removing the power. If it does not beep, then it could very well be your motherboard. Secondly, you might try removing the hard drive( if applicable) and memory. Power the unit up to see if it responds to no memory. If it does, put just the memory back in and see it you get the “Lenovo” logo. If you do, power it down and put the hard drive back in. Try booting it again. If it does not come up with logo then your hard drive is bad and simply needs to be replaced.
Hope this helps.