I'm having a hard time removing Ubuntu so my question is, if I reset my Windows 8 with "Fully clean the drive" option in the reset my PC mode, will it remove all Ubuntu partitions, Grub etc.?
Windows will automatically remove the Ubuntu OS, when you install from a set of Restore discs. I keep a back up on a NAS of my Windows install and Xubuntu. So that way if I need to go back to use Windows, I can swap images using Clonezilla.
I've acquired PC's with Linux on the HD and to clean it off so I could use it exclusively for Windows,
I've booted up the PC with my DOS Utilities CD and ran FDISK and 'Remove Non Dos Partitions'.
That removes the Linux partition so I could then set up a standard Dos partition. Windows will install to that with No problems.