Thankyou very much for such a speedy reply Ian.
Just in case anyone else has the same issue I'll say what fixed it.
Firstly, I downloaded the drivers from the link above that Ian gave.
I also got some windows 7 drivers for my ATI graphics card as well!
The disk driver application said that "This computer does not meet the minimum requirements for installing the software" so I googled that phrase and found out what was wrong.
The shop I bought my PC at had left the drive controller as an IDE type in the BIOS. I needed to change this to AHCI and then reboot.
My copy of windows would then not reboot and it attempted to repair the disk by itself. This failed and I had to reinstalled Win7 from the DVD.
The Intel drivers you linked to then went in straight away and I now have write caching enabled.
My machine now boots up in about 30 seconds so it's much better there as well.
Once again thanks for your help.
-Orange peel