This is why you needed to make the Acer Recovery disks when you set up your PC, so you'd have a backup method in case Recovery fails which it can do.
Your options now are to call Acer Tech Support to order the Recovery disks, or to follow the steps in this tutorial to Clean Reinstall - Factory OEM Windows 7
. Everything you need is in the link to get a superior install without the factory bloatware and duplicate utilities.
You would already know that the latest Win7 installer is provided if you'd even bothered to read the tutorial, so you need to decide now if you're going to be thorough to get the best possible install, asking back all the questions needed to get it done right. If not then order your Recovery disks or take it to a shop.