ok so now my max transfer rate is set at 0x00FFFFF, I've read that that is should be 0x1fe00 BUT if I change this figure now will I lose/ affect existing data??
You can change it. I bet it's very likely that which is causing your problems. Wrong value makes random read errors which makes your programs crash. Especially if you have the same system cloned on the new device and it has worked fine with the old HD... but anyway, when using CF cards on internal IDE port, it really should be that 0x1fe00.
