Hello group

For decades almost I have been satisfied with using serial DCC to
transfer needed files occasionaly between mostly DOS, and win 98
computers. I'ts pretty slow but reliable.
I now have 2 win xp home sp3 computers to deal with as well, one is a
pentium II platform. The other is an Intel Atom high speed, huge RAM,
huge HDD Netbook.
All machines have ethernet hardware, though I've never put my hand
into that.
I have a wireless, and a wired type routers, whatever they're for.
I can live with not being able to do file transfers in the background
while doing something else on the active window but prefer the former.
I can't spend much money.
My questions:

A - Could I Direct Cable Connect more than 2 machines at once? Is it
even feasible? What kind of cable setup?

B - If I couldn't, what would be a Simple way of using the ethernet
function to achieve more than 2 machines?

C - Is using the fastest machine with the most memory as the server
(sender) machine faster than using a slower one? (my intuition says
yes)

Thanking you in advance

douglas