Creating an up to date windows 7 iso with all updates

Hi guys, I work in a store that formats second hand laptops and sell them on.
We use the product keys that are already on the bottom of the machines, so the discs I want to create should be fully legit and need activating once installed.

I've seen on this website: The Last Windows 7 ISO You’ll Ever Need: How to Slipstream the Convenience Rollup

This gives a tutorial on how to set one up but as we are not overly confident in doing it correctly we wondered if there was a pre made version that exists somewhere. It doesn't need to be 100% up to date, more passed that one update which can take several hours to complete.

Also as an added bonus, is there an option when creating an iso to have a huge library of drivers so once the machine installs onto the computer, the drivers get installed as well (similar to windows 10)

I hope I put this on the right sub forum
Thanks for any help :)

Using nlite which is free does all the hard work for you and simple to use

Instead of formatting the disk and installing all drivers, why don't you use the Factory Recover from BIOS? It will format the C: partition and load a disk image from the recover partition, with all drivers installed. It will be as it came from the manufacture.

Once you boot it and get to the point to create a user, launch sysprep. As an administrator install all updates and when done leave sysprep. The computer will be as new, activated and with the updates installed.

For the updates MS releases SP2 for Windows 7 - Windows 7 Help Forums