you dont. you can contact acer to purchase new recovery discs. you can also try this:
To access the recovery partition on your Acer computer for recovery, follow the steps listed below.
1. Power on the computer
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
Note that all data will be lost during this process and your computer will be brought back to it's original factory state and settings.http://www.geekpolice.net/t7449-acer-system-recovery-partition-hotkey-instructions-erecovery