Very STRANGE LAN connection problem

I purchased two new laptops (Dell) for Dr.'s office.
The office is new. They have DSL through Bellsouth.
I have DSL through Bellsouth at home. At home,
both laptops connect immediately - no problem.

At the Dr.'s office, neither will even though there are
two other computers there which connect with no
problem. I have tried known
good cat5e patch cables. In fact, I took them to the dsl modem
and connected them directly with known good cable,
they won't connect. There are two other computers
there which have no problem connecting.

I DON'T get it. Any help please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!