Check your user guide. Usually you'll find the procedure there. It probably gave instructions for creating the discs to restore to factory settings there. If you don't have those discs, contact Acer and see if they will send them to you for a small fee.
When you've gotten your system back like you want it, I urge you to get yourself an external hard drive and a good 3rd party backup program. You can set it up to do everything automagically at the time and frequency of your choice. 1 TB external hard drives are about $60 these days and a really good FREE backup program is the Easeus Todo Backup Free. That can save you a lot of time and frustration the next time something like this happens. Sooner or later it happens to all computers for one reason or another.