Why can't I connect to a router wirelessly

All the desktops and notebooks in our company can be connected to the wireless internet. And all the other notebooks have a built-in wireless card. My machine is a bit old, it's Dell Inspiron 2650, and the wireless card is Linksys WPC11. My machine used to be connected, but not since the beginning of last week. If I reactivate the NIC, it will disconnect again after a few seconds of the connection. And I can't use WEP and WPA, but I'm using a MAC address filter and my address is on the list. You are in urgent need of your help.

Intermittent connections that indicate incompatibilities in your network security system, inability to obtain IP addresses via DHCP, or weak signals. You should check to see if the machine has been altered during the period of these problems. Some possible changes, such as:

Whether the software and configuration in your notebook have changed. Do you have a new patch or service pack that will affect your network connection configuration? Then you have to remove them and then reload the wireless connection (using the Control Panel), remove and reload your wireless card (using Device Manager), or use the System Restore to find the date when your NIC last used normally. Check out the XP event log to see if you can find out when the problem started and what happened to the system on the day of the problem.

Whether there is a change to the router's firmware or structure. Have you upgraded your router's firmware, or have you set up another MAC address in your router's ACL? Or did you restart the router during the time you found the problem? If you assume that no other device is having a problem, a simple router problem is unlikely to lead to a situation like yours, It is likely that your ACL entry has been compromised. You can remove the Mac entry and reinstall it, or temporarily interrupt the ACL. Check the router's log when you connect, and the error messages will help you identify the cause of the problem.

Changes to the wireless network itself. There are often some external environmental reasons that can affect the strength and coverage of the signal, so it is likely that a new source of interference will cause problems with your machine. If a node is unable to connect, try other sites closer to the router. Also check that there is another point that also applies to your MAC address or your computer's IP address? or your router or other machines in your office use the "g-only" mode, which will also interfere with your previous 802.11B card and check your router log.

There may be a problem with the wireless card. I often find problems by installing a problematic NIC on another machine, and if the same problem occurs on several other machines, I have reason to suspect that there is a problem with the wireless card or its firmware, not the laptop. Usually the problem is software rather than hardware, but don't ignore hardware. If you really suspect a problem with the NIC, you can upgrade the firmware of the network adapter. You can also buy a new 802.11g network card, now the wireless card is not expensive, buy new is very worthwhile.

Please note: I do not recommend that you check your WEP keys or WPA PSK because you say these systems are already invalid in your router. However, the situation you describe is very common, and routers often do not match the WEP key or PSK in them, so it is often possible to look at their problems before considering other possibilities.