Internet access errors

[AlbertLionheart]

Anyone any ideas on this?
3-Com router with 2 PCs connected to it, neither of the PCs can access the internet despite them both showing messages that the internet connection is running. These PCs both have fixed IP addresses although changing them to dynamic makes no difference.
A ping from the PC to (say) google.com does not respond.
A ping to the router (gateway address) and other PCs on the network is fine.
I can access the router setup through the browser to the gateway IP address and the router diagnostics all show everything working fine - happy happy joy joy.
The router is connected to the ISP and will ping and resolve google.com without error.
A third PC (my laptop which I know works perfectly on my home network) also fails to connect to the internet.
I have not yet reset the router as the client has lost his ADSL account password. Grrreat.
I have not poked about with ports yet but it might be worth doing maybe...
Any ideas why the PCs cannot access the 'net?

 

[raybay]

You are an oldtimer, who knows the ropes... so...
Did it once work, or is this a new install?
Did it work on one PC?
Can you get back to a simpler setup when it did work, and start over from there?
I would start over with one router. Remove all your installed software for that router.
In essence, start over.
You have missed something simple and obvious. You will find it.
Sometimes it is easier and less time consuming to start over than to find and fix, as you know.

 

[AlbertLionheart]

Hi Raybay
This is an old setup and I put in place a couple of years ago and which had worked without error since then.
Today I disconnected everything except 1 PC which was my laptop, and using a cable I know is good - no internet access. I confirm I could access the router setup through the browser and the diags and logs all show everything is working - just that the PC can't see anything beyond the router.
What you say makes me almost certain it is the router but I dread having to set this up again as there are complications I have not mentioned as they do not apply as I had them all disconnected and the rest rebooted before starting to work on it.

 

[raybay]

Yeah, I know that feeling...
But whatever doesn't kill us, makes us stronger... sometimes.