Just about all laptops come with a recovery partition on the HDD . As long as you haven't removed it using this would be the quickest & easiest way - the exact method of doing this will depend on the make & model of laptop, but Google will find the instructions I'm sure.
did you create the recovery media when you first setup the laptop? If you did then this would be much the same as recovering from the recovery partition.
Other than that you need the correct media and your license key to do a manual clean install. This will probably take longer and is not as easy, but at least you wont have all the pre-installed bloatware that comes on all laptops these days. Just be aware that you are likely to need to download drivers, so make sure you get them first or have another computer to get hold of them.
Mark.