I have installed Windows 7 on a blank hard-drive in a Toshiba C660.
This page lists the download locations for Windows 7 ISOs as hosted for Microsoft.
You should check your Windows sticker (usually located underneath your laptop) to find out which edition you own, download the matching ISO, burn it to a DVD and Install it using the Product Key on the aforementioned sticker.
You Windows sticker will look something like this:
Note that you will also require drivers, all of which will install on first login, but WiFi will not work so make sure you can connect via Ethernet before trying this.