For anyone who might be having a similar problem!
I fixed it by using Norton utilities and choosing the option to defrag free space and then to wipe it. Win defrag does not appear to give enough control to sort the problem.
Even after i had done a full optimization defrag with norton it still left this 'infreq used' area at end of drive. So do a full derfrag and then defrag free space and wipe. Oh and and I was able to leave virtual mem as normal as well as the win swap file as norton had moved all to the front of drive. Good luck