Thanks, I got it all working. The drive I purchased was actually faulty, I got the same model again, activated 2 partitions, made one active and ensured that drive was under 200GB ( it seems some older model motherboards don't like bigger!). After a few trials and errors I got it installed. As regards the SATA cables, I was installing the new drive directly into the old slot on the motherboard and booting from an external CD Drive as my internal was also problematic so there shouldn't have been a power problem.
I later had some issues with windows 7 drivers not recognising my graphics card (coprocessor), after trawling through hours of blogs and being entirely unsuccessful I found one guy who reccommended installing DriverMax software... I couldn't reccommend it more!! it really solved my problems both recognising and naming the hardware and tracking relevant drivers. Their free account also allows you 2 free driver downloads per day, the best driver helper I've tried by far.
Thanks again for the help.