I,ve just found my receipt from Dell and the specs, which don't mean a thing to me, but perhaps someone could understand them and it may give a better picture of what I've got!

Dimension 5150 Pentium 4 630 (3.00)~Dimension 5150 Pentium 4 Processor 630 with HT Technology(3.00GHz.800MHz fsb. 2MB cache.

1GB RAM 160GB HDD

160G(7200rpm) NCQ SATA HARD DRIVE.

I've copied this from the paperwork, some of it looks as though it's repeated but that's how it's written down.