Operating system gone after reset interrupted

[funkmaster223]

I reset my Acer 7551 but I interrupted it and now I have no operating system

 

[Saga Lout]

When you power up the machine, do you see on the black screen an option to press a Function key for Recovery?

It's your only hope unless you have a Windows DVD and a readable product key on the Certificate of Authenticity on the laptop's case.