This isn't a general rule, but almost any released laptop has a recovery partition that can be accessed during the first stages of boot. Reboot the Acer PC and watch closely for a recovery mode button. Press it and then follow the wizard guide. All the instructions will be presented in an easy manner for a better understanding.
If you still encounter issues, consult the manual of the PC using the Support CD that arrived with your laptop or access the Support page provided for Acer customers.