Hi
Is PC/Laptop still working ?
Usually there is an option to create recovery DVD set which can be used if hard disk dies and gets replaced
(instructions in Acer user guide)
If you can't create recovery DVD set then contact Acer who can sell you a recovery DVD set
Or buy a Microsoft Windows 7 or 8 DVD
(if hard disk still has Vista on it you can buy an upgrade version)
(you will need to download drivers from Acer website for motherboard, graphics, power, network etc)
regards
Mike Barnes