Just cause a PC recognizes the drive doesnt mean the BIOS will be happy with it and be able to successfully boot from it. Check that the BIOS is reading the drive correctly. If it allows you to see if the BIOS can Detect the drive and that it configures it correctly. SATA drives dont require jumpers especially in this situation as there is only 2 plugs on a sata cable one to MOBO the other to HDD not like IDE where there are options for Master and slave on the same cable. You can add drives and cables to the system. Make sure the drive you plan to use/boot from is connected to SATA 0 What is your optical drive SATA or IDE ? And what is it set to. If it helps PM me i will give you me number and we can talk through some stuff. This has got to be one of the worst ways to solve PC issues. Give me the system i will have it sorted in no time, Never been real good at theorizing.
Just to add Demacoz has way more experience than me and i would lean towards him if you need more answers I've only been in this game for just over 9 years and the more i learn the more i realize the less i know.

Thanks for ideas

Leaning towards mother board bios been problem. Bios on this machine wont support more than 2 gig of ram either.

So to keep wife happy, organising her new machine, will put 2 TB drive into it as well, so she can backup onto this drive

thanks Andy. anytime you need a Mainframe designed i am your man

Ditto - I have to archive bits of my brain all the time.

the only way I stay sane is to do stuff outside of work like sport or the datto

Try updating the motherboard bios to the latest version.