It only says Priminfo on the power button and some numbers and codes that doesnt do anything...
I just want to know the model and the full specs and the guide.
depending on where it was purchased;
it could have been a lower quality OEM build with customizable options from an extinct company.
this could make finding the exact specs near to impossible without pulling out the components and identifying them yourself.
or it could've been a customizable build from a smaller retail shop that may have no exact model or specs determination.
if it is an OEM pre-built there will be a sticker located somewhere on the chassis.
underneath, somewhere on the interior, behind the motherboard, etc.
this would have a make\model listing along with serial and\or UPC #s.
if you are serious about purchasing it ~2007 than finding out an actual make\model for this specific system would do you almost no good anyway.
anything in it would be so old that replacing with exact or compatible components would be a waste of money.
any new even budget-priced parts would be a much better deal with much better performance.
by "guide" i imagine you mean user manual.
even if you find a make & model for the system, finding an existing user manual online may still be impossible.
if it turns out to be a very popular model you may find some owners that have uploaded a .pdf of the manual somewhere, but most manufacturers don't still offer downloads for such old products.
maybe explaining why exactly you want this information could help with your situation.
are you just curious or planning on some hardware changes within the system?