How to reset Acer Aspire 5315 notebook to factory setting

usually you need to press Alt and F10 to access recovery partition.

There are two basic ways to restore Acer 5315 PC Notebook to the original setting. The first method you can try to pressing the key Alt + F10 for 5 times while startup process appears on the Acer screen. Usually this way will restore the original setting automatically.
Follow this guide:
Windows Vista System Restore Guide

There are two basic ways to restore Acer 5315 PC Notebook to the original setting. The first method you can try to pressing the key Alt + F10 for 5 times while startup process appears on the Acer screen. Usually this way will restore the original setting automatically.
And the next method you may need to use system restore at the first time you’ve got your Acer 5315 laptop. Here are steps to follow:
Log on as the Administrator => Start => All Programs => Accessories => System Tools => and click the System Restore. System restore will run and here you should see the Welcome System Restore page appear. Click Restore my computer button to an early time if it’s not already
selected. Click next to continue the steps.
There is on your Acer 5315 laptop screen a Restore Point page appear, you can select it and then click the most recent system checkpoint it, click a restore point list. After you click the Next button, System Restore message may appear that lists configuration changes that
System Restore will create. Click OK.
For the last step click next button on the Confirm Restore Point Selection page. Now the ‘System Restore’ will restore the previous Windows XP configuration on your Acer 5315 OS system. Just finish it by restarts your Acer laptop.
Now log on again to your Acer 5315 PC Notebook as Administrator and watch the System Restore Restoration Complete page appears. Click OK.

Press Ctrl+F11 or F8.Select Repair My Computer.
Choosethe factory reset option

Yes, Usually when you purchase a computer, the computer manufacturer has set a certain key or keys that you can press if you ever wish to reset your computer back to its factory settings. If your computer is still the same way now as it was when you purchased it, then pretty much all you have to do is contact your computer manufacturer, or read your paperwork/owner's manual ( this might be on a cd), or maybe even go to your manufacturer's website and search. Either one of these ways should give you the way to reset your computer. Hope this helps!