Problem with network adaptor

Hi, I wondered if anyone knows the problem with my Imac. Its a Apple iMac "Core 2 Duo" 2.4 20-Inch (Early 2008). It will not connect to the internet either by eathnet or wirelessly. I know its not the modem or the ISP problem as a windows laptop I have connects both wired and wirelessly. In network prefs it gives an IP address starting 169 although it does say the eathnet is connected. Wirelessly it connects to the hub but says there is no internet access. I contacted my ISP and they checked the modem and its all working correctly. They said it was the network adaptor on my Imac. However I can not find any answers on the internet about what I can do to replace it. Can you even replace the network adaptor on an Imac
Thanks

If a Windows box can connect to the internet both wired and wirelessly then the modem hardware is not likely the problem. Since the iMac is not connecting by ethernet or wirelessly I would look at a configuration issue before hardware. If the problem were with the iMac's wireless card alone you should be able to connect wirelessly if the configuration is correct.

The 159 address means that the Mac is not able to get a valid IP number from the modem/router. Can you tell us a bit more about your setup. What model modem are you using and is the router separate or built in to the modem? Model numbers would be helpful.

They are wrong in the sense that a Network Adapter is either the Wired or Wireless NIC and they are separate hardware. If both are getting a 169.x.x.x IP, then it sounds like more like the modem/router is not giving out another IP address to the iMac.

Like Sly asked, what brand is the modem/router? Model number? Is it set for DHCP? If not it can only hand out ONE IP address which it's already handed out to your Windows machine.

Give us a bit more info please. I own that exact 2.4Ghz C2d iMac and both WiFi and Wired connect to any router I have used it with. Also what version of OSX?

Also does your Network have MAC filtering turned on? This is not a means of locking out Mac computers it's based on the ID number for your network adapters (no matter what brand computer or OS). If that is on your machine won't get through till we make some changes to the setup.

Yes, It goes by the computers MAC address. Very good point also.

re above

Im running lion on my mac. The modem is a built in wireless thing. Its a NetgearVMDG280. Its supplied by the ISP Virgin in the UK. I dont know what you mean by mac filtering and i left the settings in network prefs the same as before. The modem is brand new as the internet went off on the mac and Virgin jstswnt me a modem to se if that was the problem but it did not work before whan it was just hardwired to the old modem.

Sorry rushed the above and thanks for your interest.
Im running lion on my mac. The modem is a NetgearVMDG280. It has built in wireless. Its supplied by the ISP Virgin in the UK. I dont know what you mean by mac filtering but it does have a sticker with a number on it and NAC written on it. I left the settings in network prefs the same as they have aways been. The modem is brand new as the internet went off so I rang the ISP and they sent a new modem. I tried it without connecting any other computers both wired and wireless but no joy. Then tried it with an old laptop I have and it connected, so they said the network adaptor on my mac must be U/S. The ethernet says its active and has the ip address 169.254.130.241. Its using DHCP. The WI FI says its connected to the network but the ip address is 169.254.19.185. Hope this was the info you were requiring

That is indeed interesting. A New Router/Modem out of the box would have no MAC filtering turned on. Let me find the manual on that router and will tell you a few things to check on.

I am behind here so it might be later today as I still have to check my USB Trackpad in GTA SA for a user to see if it works. Will get back to you later.

No problem, Thanks Dennis

By way of update. When I go into the web address for my modem/router and connect my mac via eathernet it shows up in the "mac filtering" tab. It shows the following for the mac
Device Name IP Address MAC Address Interface
192.168.0.2 00:1f:5b:ee:d4:9d Eth-Switch Lan(1)
However still nothing connects to the internet on the mac.
Nothing shows via wi fi.

For your info. I dont know what I ve done but its working now. I logged into one account then back into the admin account and all was working fine. Sorry to waste everyones time and thanks for your interest.
Mike

Not a waste of time at all. Glad it's working. If you have trouble down the road, we will be glad to help.