"MAC address is not defined" error message in windows 7

I am having a Dell latitude laptop, this is running with windows 7 OS. my laptop is specified with intel processor, along with ATI radeon graphical interface, 3 GB RAM,320 GB hard drive and inbuilt specified with wifi connectivity. I usually connect my laptop with wireless network from both ,my home and office, the machine was working fine till the last date. But suddenly from last two days back whenever I tried to connect my laptop with the wireless network it flashes a message that the "MAC address is not defined". I am not having such information regarding this type of problem. What should I do to overcome from this problem? Any suggestion for me to resolve this suddenly happened problem.

According to the problem that you mentioned in your post, might also be occurred for the network router that you are using, for that I suggest you one process, simply ping to the device manager from control panel, and from there open the network tab and right click on the router name, choose the update option, select online update option, it will collect the update information of the router firmware that you are using. Download and install the desire version into your system, now reboot the router and also the system and try to connect the system with the network, I hope by update the firmware version the problem will surely be solved.

I would like to recommend you to reset the internet connection that you are using. For that proceed to the network and sharing windows from control panel, and open the network service, now click on reset option, it will ask you to remove the internet setting that you set earlier, remove them and reinsert the information’s again in to the desire places, along with also put the MAC address, restart the system for applying the changes, I hope it will help you some how to resolve the issue.

I also thing that the problem is for the router for that, first of all check the router status from device manager and be sure that router is working fine with all of its functions and the features. Did you tried with the other network or the router whether the same problem is arriving or not? Try this, if the similar issue is arriving there then the problem might be inter connectivity that you configured in your system, for this apply the reconfiguration process, and by this the problem is not solved then simply reinstall the router driver that is installed in your system. Along with this also like to suggest you to check the wifi or MAC address from settings of the network and sharing, make sure that you insert the correct the MAC address of the machine.