How can I remove photos added to my iPad from my PC and laptop?

You use the same process that you used to get the photos on the iPad to begin with. Photos that were synced from your computer using iTunes can only be deleted by de-selecting them from the folder from where they were synced - and then re-syncing.

So that means that you have to connect your iPd to your computer, launch iTunes, select your iPad under the devices heading in the sidebar, click on the Photos Tab on the right and then uncheck the folder of photos that you synced to the iPad and then click on Apply in the lower right corner of iTunes.

If you want to remove all of the photos, uncheck the Sync Photos From Heading and then click on Apply.