Vista Network Connectivity Problem

I have bought a new Vista Ultimate computer recently. I have already set it up and it is connected into the wireless ADSL router/modem that also serves as a server and also acts as a DHCP server, which I use for business and other laptops that connect locally and some remotely. I was not having any connectivity issues for a couple of weeks, but recently today I checked that the network ico was showing some Limited Connectivity? So, I unplugged the ethernet cable from the pc and then after waiting for some seconds plugged it back and then it reconnected to the router and the internet also. I thought this problem might not occur but again after sometime the same issue started. So, to fix this issue I have tried resetting the router, restarting the computer, etc, but nothing seems to be working. If anyone has got some ideas, then please share it with me. Thanks.

Try anyone of the below fix and see if that works for you:

1. If your computer is currently connected to the Internet and the LAN without any connection problem, you may want to disable the message "Limited or No Connectivity".
2. If you are using DHCP, verify DHCP server is available on your network and other computers can access it.
3. Download and install the Update for Windows XP Service Pack 2 (KB884020)
4. Check hardware connection and configuration.
5. If you are using wireless, check this page, Sent packets only on a wireless computer and Limited or no connection
6. Check firewall, spyware and winsock settings.

It might be possible that Windows Vista is not able obtain an IP address from certain routers or from certain non-Microsoft DHCP servers. This issue occurs because of a difference in design between Windows Vista and Windows XP Service Pack 2 (SP2). Specifically, in Windows XP SP2, the BROADCAST flag in DHCP discovery packets is set to 0 (disabled). To solve this issue, go to this link - http://support.microsoft.com/kb/928233/en-us

You might be also experiencing connectivity issues or performance issues when you connect a mobile PC that is running Windows Vista to a wireless access point. To work around this issue, use one of the following methods, as appropriate for your situation described here - http://support.microsoft.com/kb/928152/en-us