Boot from recovery.
1. Power on the machine
2. At the white ACER BIOS screen, hold the “Alt” key and press the “F10” key simultaneously to start Acer eRecovery
3. Once eRecovery has loaded, click “Restore to Factory Default Settings”
4. Click “OK” to continue
5. From here, the eRecovery process will update all the data on the C: drive and restore a fully functional factory image (approximately 10 minutes).
6. Once eRecovery has run, press “OK” to reboot unit
Will probably delete all your shit though.