Resetting Laptop

Hi,

I need to return my computer to basic Win7 Home premium 64 bit so I can sell it. I unknowingly deleted the Recovery files and have lost the recovery disk I made. If I get an ISO of the correct Windows software, and enter my product key, firstly will this work to achieve the goal I want and secondly will a company be able to tell the difference?

Reply to me in IRC or message me on reddit at /u/Conrad9

Thanks