This is a complicated process that, if performed incorrectly, may leave your Windows partition un-bootable. We encourage you to visit the IT Helpdesk for help if you are looking to remove a dual-boot partition. If you decide to do this on your own, please follow exactly the steps in this guide. And remember - always keep your data backed up!
The first thing you must determine is whether your machine is booting with Legacy BIOS or UEFI. To do this, reboot your machine, and go to Setup by hitting F2 when the Dell logo appears. Then, go to Boot Sequence, and make note if you have UEFI or Legacy checked. Follow the appropriate guide below.
Instructions adapted from here: http://linuxbsdos.com/2015/09/05/how-to-delete-grub-files-from-a-boot-efi-partition-in-windows-10/.
These commands are used to identify and select the hard drive
These commands are used to list the partitions, select the Boot EFI partition, then assign it a drive letter
These commands are used to change into the Boot EFI folder and delete the GRUB folder