<human>: I have an old PC which works fine but is in pieces as I built a new machine and used some of the parts.

I have just realised that the old machine still has some stuff on the HDD that I need, is there any way to get this onto my new machine without building the old one up and copying the files onto a USB stick or whatever.

I was hoping to set it up on this new PC and have two HDD for added storage.

Oh and if it helps, this new machine is running Windows 7 and the old one is XP.

Provide a brief overview of the text.
<bot>: Old PC running Windows XP, new one running Windows 7. Can I use the old Win XP HDD on my new machine and if so, how?