Roko wrote:
So this means I would be able to connect the HiFi speakers to the
computer if I had an amplifier (of satisfactory quality) which would
be put between the two? Of course, that would require some necessary
tweaks and I would actually end up building a receiver? And another
of course: if not building a brand new amplifier from the very
beginning, I would have gotten it from another HiFi receiver, and
that again would make no sense doing because the amplifier, as
ShadowTek said, is the main value of a receiver and then I could have
just as well connected the speakers through the existing receiver?
Sooo, if the answers to the above questions are all "yes", the only
sane thing to do is to buy a new HiFi receiver - that would actually
prove to be the cheapest solution then?
Once again, thank you all for your time and patience 
Yep a new hi-fi amplifier (commonly confusingly misnamed 'receiver'), or
your old one if physically close to your computer.
geoff