The Mega-Ultra-Famous Issue : deleting Linux and not Grub-Loader !
Now ! I have a Dell-Tower-PC, with genuine winXP and No Operating System CD ! (a FreeDOS instead) !!!!
What I have to DO !!!!!!!
PS: I extended the C: Partition so Now there is only 1 Partition, (Instead of 2. one for WinXP and the other for Linux, So Using the Windows 8 Disk Management, I do delete the 2nd Partition and the Swap Partition and then extend the 1st Partition wich it containing WinXP of course !)
I feel your pain, I had a dual boot on my computer and decided to remove Linux...and GRUB. The problem is that Linux and GRUB are tied together (so to speak) and if you take Linux off, GRUB is going with is. What I recommend doing is getting the Windows boot manager (if that is possible and legal) off of the internet or getting an independent version of GRUB that can replace the one with Linux that is on your computer now.
If neither of these sounds all that appealing, you could try to access to all of the Linux files from Windows and delete all but those related to GRUB. I have never tried this myself and I am not sure if it is possible, so I would try the above methods first.