While using P.I.N.G. to make a backup of a machine I chose to shrink the partition before taking an image, this was necessary as I did not have either the space or time to wait for a 320Gb image to be created over a network connection.
P.I.N.G. uses the linux utility ntfsresize to work out how small the partition can be, resizes the partition then takes an image of it. Unfortunately in this instance when finished it did not resize the partition back to full size (I am unsure if it should by default)
This left me with the situation that Windows XP thought it had a 320Gb hard drive with an 11Gb partition, being unable to save any further data to the disk meant that windows was an unhappy bunny.
In theory I could use ntfsresize from the command line to expand the partition to fill the hard drive again, however when I tried this I was getting various error messages about not being able to access the drive.
Step in GParted and the ever useful Ubuntu bootable USB Stick, simply boot into the Ubuntu system, right click the disk you need to work on and select "Resize/Move" simply reduce the size by 1 meg and click apply, then click the green tick to apply the settings, close out of GParted and rebooth the machine back into windows, you should find that the partition is correctly showing as the full size minus 1 meg.