You will need access to recovery files on your Acer E1-531 laptop if you want it to restore to factory settings. For this, Acer includes a recovery partition that can be fired up when your computer boots. However, for some reason, if you changed your hard disk or by mistake, deleted the recovery partition, you will not be able to perform the recovery process.
Fortunately, Acer provides something called eRecovery that lets you buy a recovery image on a DVD or flash drive. On that page, just enter your serial number and click on submit. Acer e1 531 specs and price.
Then, you will be asked whether you want a DVD or flash drive. Enter your address and get recovery disks/drive delivered straight to your home.