Call Packard Bell for support if still under warranty, basically the most likely solution would be to use F8 when rebooting (unplug battery, use wall power only, unplug wall power.. plug in wall power, turn on) hitting it repeatedly till you get the 'menu' and select to restore your Windows 8 (assuming it is a W8 machine). That should restore it back to working from last it was backedup. If it can't then you will have to do a complete RESTORE TO FACTORY, and your going to lose all your data. It would be the same process but would wipe the computer back to the first time you ever turned it on.