What cd/dvd are you booting from to format? You forgot to tell.
I'd download GPARTED (free), burn it to disk (using IMGBURN, free also, or your other favorite burning program that can burn a .iso file to disk as image) and use that to delete the current partition and make a nice new one.
The alternative is downloading DBAN (free), burn it to disk and use that to totally erase the disk (like it's totally new). Then the Windows 7 installer (assume that is what you try to run) shouldn't give any problems, unless the power cut damaged the hardware.
The nice thing about laptops: they have a battery, so even if you run with an adapter, they just continue to work for a few hours if there's no more power from the mains.
Doesn't your laptop have a battery?
I was going to format my pc and everything was ok when the power was cut and my laptop shut down. When the power came back on i booted again from cd/dvd trying to re-do the format but i was unable to. After loading the files to boot, it never went back to the select language screen it just gets to starting windows screen (black) and doing nothing it just stays there and i can't format it... what can i do? what happened?