Hello,my display gets lines across it then my aspire5515 reboots itself
The system error (probably graphic driver) is causing the Auto reboot.
If you can boot into safe mode, try to update the driver, or if you recently had a windows update, roll back the driver in driver details. Just assuming it is the grphics due to lines across your screen. Use other options in safe mode if you have to, including stopping the auto restart by disable auto restart on system error.