search 'how to restore to factory settings ….' and put your brand of laptop and version of windows.
if your having issues loading into windows, put 'from bootup' on the end of the search
you will find instructions on how to wipe and reinstall the operating system, drivers and any programs that came with the laptop. this will delete all files on the laptop.
Download windows installation to a USB stick. Install from there.
Specifically- "which laptop". And what OS?
Help us answer you.
Edit: and while you are at it…would you consider Linux- or do you "need" windows?
Different methods for different systems