I remember the first time I tried to delete Linux in the late 1990s. I thought formating the c: drive would do the trick but nope, I had to use the command fdisk /mbr
We don't use DOS anymore, but I believe the free disk wiping software DBAN will wipe the disk and MBR at the same time. but if you have a windows system restore partition on your drive, especially if you haven't backed it up, you might want to stay away from DBAN.
Anyway, after DBAN is finished you just need to insert your Windows install DVD in the drive, start up the computer, and it should prompt you to create an NTFS partition during setup and it will install onto that