How do i master reset my acer 5220

If the system can not boot, you can restore it from the WinPE environment. The system starts from the hidden partition on the hard drive. To begin the restoration, press Alt + F10 (PC Tower) or F10 (laptop) to boot the PC and when the Acer logo appears. This will start the system from the hidden partition the hard drive and you access its main page. The restoration will be on partition C:. The partition D: (ACERDATA) will not be formatted, and therefore documents will not be deleted but it is always prudent to think about making a backup of your most important documents in case!
Note: You will be asked to enter the password before the System Restore starts. If you enter the wrong password three times, the computer will restart into the operating system.

You must enter the password to access the main page of the hidden partition. The main page of the hidden partition provides three options to restore the system:

1 - Restore the system to factory default settings: Select this option and then enter the password. The utility will restore the system from the image of the factory default settings on the hidden partition on the hard drive. When prompted, confirm the system restore. A message will warn you that you will lose all data on the disc. The utility then restores the system to its original state.
2 - Restore the system from backup user: Select this option and then enter the password. The utility restores the system from the image of the user on the second partition on the hard disk. When prompted, confirm the system restore. A message will warn you that you will lose all data on the partition. The utility then restores the system to safeguard user the most recent.
3 - Restore the system from the CD / DVD: When this option is selected, insert the first disc of the backup in the optical drive. Confirm System Restore when prompted. A message will warn you that you will lose all data on the partition. The utility will restore the system from the backup image on CD / DVD. Insert the other disks when prompted.

Note: If you are trying to restore the system to its factory default settings stored on CDs / DVDs, Acer eRecovery Management prompts you to insert disc 2 to start.

Good Luck