WRT45G: can only connect one pc at the time to internet, cannot login to router setup

Question

Hello,
I don't get this. The complete network worked fine for ... years? After a call with the ISP about a general/different issue, we can now only connect one pc at the time to internet. (We were asked to take out cables and we've put them back).
I've been trying and searching for an answer for hours.
problem:
We can only connect through the router to internet with only one pc at the time (the first pc we connect after starting up the router).
Also we cannot get into the setup menu of the router at 192.168.1.1
We've been trying to reset the modem for 10, 30 seconds.
Auto resolve IP/DNS. DHCP is enabled.
I also remembered that I pushed the SES button, it turned from orange to flashing bluish. I never knew aboutthis function, nor it is mentioned in the manual I downloaded. Now this SES indicator is off.
Also WLAN and DMZ led are off.
I downloaded EasyLink_Connect.exe, went through the setup. It recognises there's internet connection, but stops and says: cisco does not support this modem.
Temp. replacing this WRT45G modem with another one did not resolve the issue.
I have no clue what went wrong, what we did wrong, and how we can resolve this issue? Please help! Thanks
Message Edited by Brammm on 11-27-2008 03:13 PM

Answer 1

Okay! 
1.  (results when having assigned a static IP) :
 Windows IP-configuratie
         Primair DNS-achtervoegsel. . . . .:
        Knooppunttype: . . . . . . . . . .: onbekend     (unknown)
        IP-routering ingeschakeld. . . . .: nee      (no)
        WINS-proxy ingeschakeld . . . . . : nee    (no)
 Ethernet-adapter LAN-verbinding:
         Verbindingsspec. DNS-achtervoegsel:
        Beschrijving . . . . . . . . . . .:
          VIA Compatable Fast Ethernet Adapter
        Fysiek adres. . . . . . . . . . . : 00-16-17-CE-D5-40
        DHCP ingeschakeld:. . . . . . . . : nee    (no)
        IP-adres. . . . . . . . . . . . . : 192.168.1.20
        Subnetmasker. . . . . . . . . . . : 255.255.255.0
        Standaardgateway. . . . . . . . . : 192.168.1.1
        DNS-servers . . . . . . . . . . . : 192.168.1.1
 (results without having assigned a static IP: automatic config.) :  
 Ethernet-adapter LAN-verbinding: 
        Verbindingsspec. DNS-achtervoegsel:
        Beschrijving . . . . . . . . . . .:
          VIA Compatable Fast Ethernet Adapter
        Fysiek adres. . . . . . . . . . . : 00-16-17-CE-D5-40
        DHCP ingeshakeld. . . . . . . . . : ja     (yes)
        Autom. configuratie ingeschakeld. : ja       (yes)
        IP-adres. . . . . . . . . . . . . : 84.30.99.32       
Subnetmasker. . . . . . . . . . . : 255.255.254.0       
Standaardgateway. . . . . . . . . : 84.30.98.1       
DHCP-server . . . . . . . . . . . : 213.51.144.90
        DNS-servers . . . . . . . . . . . : 212.54.40.25
                                            212.54.35.25
2.  I do have another router, when I try that one, the problem we have remains. So that's a bit strange to me. That one is supposed to be working.
Does this SES function configure anything other than the modem? So, does it alter PC configurations? I have no clue.   We even start to wonder whether the ISP is able to set up their internet in a way that unables us to make use of a router? That would be ridiculous
Message Edited by Brammm on 11-30-2008 04:03 AM