Remove any USB drives, SD Cards, CD/DVDs from the system. If everything has been removed and you're still getting the error, then your hard drive has been corrupted and you will need to perform a recovery/reinstall of the OS.
Go to you BIOS(press .del key or something similar that comes up when the ACER logo is shown)
In it you will find a setting like boot order/boot priority.
Make sure that it is set to boot from your internal hard disk.
If that does not solve it you will have to download the windows iso file and then repair your PC.
Enter the bios and make sure it sees your hard drive. If it doesnt you might have to open the laptop and re-seat the hard drive. If that doesnt work and the bios doesnt see the hard drive then it most likely died
Remove any USB drives, SD Cards, CD/DVDs from the system. If everything has been removed and you're still getting the error, then your hard drive has been corrupted and you will need to perform a recovery/reinstall of the OS.