Computer wanted with these specs as a minimum, any better is a bonus.

Pentim 4 processor 2.0 Ghz,

1 GB RAM,
80gb hdd will be fine any more is a bonus

Windows Vista (32bit/64bit),
Windows 7 (32bit/64bit).

Would like a small pc tower as small as possible please.

Which ever o/s it is, it must be able have all updates installed from microsoft.

Must be working, and genuine windows, and before I part with cash, I want to see it working, and I want to check its genuine windows.

haven't you recently just bought a computer?

Yes

I have one you can have a look at