Thanks,
It's a socket 775 machine, fairly generic motherboard, so it will be on the lower sata 3gb/s running 2gb ddr2 and a low end core 2 duo chip. It has a dedicated graphics card too, but it's a really cheap passive nvidia card.
I've managed to source a further 4gb stick of ddr2 800 and a Intel quad 8400 second hand for £20 but i figured the bottle neck is mostly the hard drive.
Given it's usage, it's basically just an Internet box, I figured this would be a good upgrade for £65-£70 as opposed to building a new system.
It's currently laggy and slow, running Windows 10, no matter how much I optimise Windows.
But it does have a poor cpu, it's low on ram and of course it's running a mechanical hard drive.
Thanks and any further suggestions welcome.