VoIP works but our computers dont have a valid IP configuration!

We are setting up in a new office building that has a network. All of our phones are on VOIP. We have Windows 7 machines and a few macs.

When we connect to the network (either directly, or through a router or switch) only the phones will connect and work.

When we try to connect our machines we get the error "local are connection doesn't have a valid ip configuration"

Can anyone shed some light on this?

There is no Gateway when I look at ipconfig. I have tried resetting the logs and flushing the DNS but still nothing. No the macs do not work either. But I know there is a connection because our VoIP phones work.

You're going to have to lay out the topology for us on this one:

DNS & DHCP server is active and assigning IPs to 1 range or multiple ranges?
Did the VoiP phones come pre-programmed with an FTP pointer? PoE phones?
Can you bypass the wall jacks and plug a laptop straight into the main router?

Thanks for the response. I dont have all the answers you're looking for but I know the phones are PoE and they are working when plugged in to our switch. How can I answer the other questions?

Are you daisy chaining the desktops from the phone(s) or via a separate wall jack? Cat-5 or Cat-6 plenum cabling?

Everything goes through our switch. we have tried individually connecting each machine to the wall jack which works with phones but the same issue occurs (no default gateway). We are not daisy-chaining the computers from the phones, no.

Also I think we are using cat-5 ethernet.

Any more insights?

Your phones can call out of the office? Misconfiguration somewhere, no DG could be on main router or on server.
However, Are your desktops getting valid internal IP addresses just missing the default gateway? ex: 192.x.x.x or 10.x.x.x? If you "ipconfig" the desktops, can you see the assigned DHCP/DNS ip addresses?

Can you JOIN the domain?