Just an update to thank everyone for their help and let you know were I got to.
PC now boots Windows 7 from the 1.5 TB drive and all options on motherboard that were switched off are back on and 8GB RAM is in.
The way I got the 1.5TB drive going was to create a backup image of the working install from the 80GB drive and then restore it to the 1.5TB drive. From there I extended the C: drive to 256GB and created the other two partitions.
Only outstanding issue now is the audio driver
- I will start a separate post for that at some stage.