power in the key board of my Laptop but now display in the screen

@zed82561 for now connect an external monitor to your computer. See if that displays properly. If so, you know the issue is your LCD. If that does not work either you will have to do more troubleshooting and determine if your computer actual turns on or if it is just the power to the computer that works. Use this ThinkPad T510 T510i Hardware Maintenance Manual top work on your computer. Since you are not mentioning if there is any kind of beep code, it is most likely an LCD issue. Anything else should elicit a beep code. Check page 52 and on for further troubleshooting. Let us know if a external display shows anything.