I have dual-booted with Windows & Linux for years, and yes, there are times a person wants to delete the Linux partitions in Disk Management, and remove the dual-boot grub.
To get rid of the dual-boot Linux puts in and go back to a Windows boot only... At a C-prompt type: bootsect /nt60 C: /mbr
If you wish to format and install fresh... don't forget to re-write the partition table, otherwise the pesky dual-boot don't leave. Most systems now-a-days can use GPT for the partition table.