Help please with "cannot connect to DHCP server"

AndrewA2 · 10-06-2011, 12:51

Hello,

(First post from new member)

I have a a Motorola SB4100 cable modem which connects to internet fine with both an XP desktop and my company Vista laptop.

I am trying to connect another laptop (Dell XP SP3) and having no joy. Just getting the "cannot connect to DHCP server" message. There is no network setup, just connecting each machine separately.

I have tried the usual stuff; repowering everything, replace cables, ipconfig /release /renew etc.

If I set up a static IP address of 192.168.100.2 I can browse to the modem on 192.168.100.1; so I know I am connected OK. Once I go back to auto IP, I just get the no DHCP again.

There are 2 possibly relevant factors:

This laptop was previously working on a wireless connection successfully and I can see it is looking for a wireless connection on boot up.

The laptop was previously on a company network domain; could that be a problem?

I have now reached the limit of my knowledge and could use some help.

TIA

Andrew

Kymmy · 10-06-2011, 12:55

You do need to reboot the modem between each change of device.. Perhaps if you disable the wifi and try again with the NIC set on auto.

PS.. welcome to the forum

Peter_ · 10-06-2011, 14:32

Are you a Virginmedia if so are all the lights on on the modem such as power, receive, send, online and pc/activity if not you may need to contact technical support unless Kymmy's advice has helped.

AndrewA2 · 10-06-2011, 17:32

Thanks Kymmy,

I have rebooted modem each time I tried the attempts described above.
I will try disabling wireless this evening when I get home from work.

Masque - yes I am a Virgin Media (ex-Blueyonder ex-Telewest) customer. As I said, the modem works perfectly well with 2 other PCs, so I cannot see how anything can be wrong there.

Andrew

Kymmy · 10-06-2011, 18:26

It's more than likely to be a network card issue than a modem/VM one.. Can you try re-installing the card driver and/or testing it with another device (round at a friends house for example on their wired router)??

Peter_ · 10-06-2011, 18:49

Quote:

Originally Posted by Kymmy

It's more than likely to be a network card issue

Very likely and a relatively cheap fix from any decent computer shop.

Kymmy · 10-06-2011, 20:16

Depends if it's an internal module or a plug-in card.. remember it is a laptop

Peter_ · 10-06-2011, 20:33

Quote:

Originally Posted by Kymmy

Depends if it's an internal module or a plug-in card.. remember it is a laptop

If it has a plug in facility then it may be an easy fix, might be an idea to get it checked out by a local computer shop rather than the tech guys at PC World.

Dai · 10-06-2011, 20:42

Quote:

Originally Posted by AndrewA2

The laptop was previously on a company network domain; could that be a problem?

It's possibly set up to look for a DHCP server at a fixed address (The old domain server address)

It may be worth checking your TCP/IP settings to make sure everything is set to 'auto'

AndrewA2 · 10-06-2011, 21:35

Thanks Guys,

Disabled wireless, rebooted everything and away she went.

I am not certain if it was the wifi, as I have now re-enabled and it still works.

One happy customer.

Andrew

Kymmy · 10-06-2011, 21:37

Sounds like the wireless was still holding the priority.. Disabling it freed that up for the NIC..

Glad you;re happy