Vista's partition shrink / extend feature - cannot shrink more than a certain amount

[Participant]

Does anyone know what else I need to do to in order to alter the partition size of my hard drive? I can only shrink it by about 200Gb even though it's 1 600Gb partition. I've moved the swap file to another drive and deleted system restore / shadow copies and it still won't let me shrink it any further.

Many thanks.

 

[Clarkey]

defrag first?