hi hanibal
ok,
turn on server, make sure all pc connected to hun/switch and turn them on.
log on to server as administrator and the browse to my network connections and click all network, can u see all 5 pc's ?
i suspect u wont because u are asking the questions.
on server click start\admin tools\dhcp
this should open a window on the lert there should be an entry sumat like
+computer name.domain name.co.uk these would have been questions asked when u setup server for example
+server.work.co.uk
in the right hand window does it have a green dot or red ? next to server name.
if green then u have dhcp running on server if red then u dont
if green,
go to first pc and open network connection start\my network places\ undertasks chose \network connection\properties\tcp/ip\ properties
select button for obtain ip automatically
then start\control panel\system\computer name and check that the workstation has the same domain name as server as above domain is work, if it isnt then click on change and follow sceen prompts.
it will ask u what domain u want to join and will ask for a user name and password for accsess, this may take a min or so.
eventually it should say welcome to the work domain u need to reboot.
reboot pc and then log on with admin (server) account making sure in the three line when u boot pc are visable user name, password and domain, if it says this computer in the bottom line click the down arrow for the work domain.
give that a try
if that works do for all pc's, u will then need to setup users on server so they log in with there own logins not admin.
ps where abouts are u in country ? what town/city ? it maybe im close...pm if u wish