Windows 7: How do I Reformat Multi Partition External Hard Drive

I want to reformat an existing external HD for backup. Currently it has 3 partitions:
1 x Primary NTFS; 1 x Free Space; 1 x Logical NTFS.
Can someone please advise how to reformat this into a single NTFS partition? I'm running Windows 7.

If there's no data on the drive that needs to be saved, just go into Disk Management and remove the partitions, until you have a blank, unallocated drive. Then create a new, solid partition for the entire drive.

I don't mess with extended and logical partitions, but you may have to delete the logical first, then the primary.

Thanks Deacon Frost.
Sorry to be ignorant, but I now have a primary partition of 260Gb with 675Gb of free space next to it. How do I make this into a new solid partition?

Again, it comes down to data. If there's nothing on the drive you need saved, you can delete that primary partition and create a new one that spans the entire drive. If you need data on the partition, you should also have an option to expand the partition out to the full drive.

Thanks again DeaconFrost, It's now sorted.