HP Pavillion dv 9500 screen stays black all the time

My laptop recently started to show vertical lines after boot up then after running for a few minutes the screen just goes black. After trying some troubleshooting tips from HP now the screen is black all the time. Removed battery, pressed the power button for 20 seconds and plugged the power cord back in. Rebooted and did a start that way but nothing changed. Removed the memory cards and reinstalled made correctly seated and removed and checked connections to hard drive. Rebooted no change.