Not connecting anymore??

I have a wireless network at home and when I fired up my laptop in the past it would automaticlly detect my network and connect....now for no apparent reason it starts up detects the network but WILL NOT connect despite my best efforts...It has me baffled...If anyone could help I would be grateful....Thank You

1.  General Questions:
     a.  Do other computers connect OK to your wireless network?
     b.  Does laptop connect OK to someone else's wireless network?
     c.  Does laptop travel back and forth between work and home wireless networks?
     d.  What operating system (and service pack level) does laptop use?

2.  Unable to make a successful wireless connection - common reasons:
     a.  Mismatched configuration
     b.  Wireless Auto Configuration is enabled and a third party wireless configuration tool is installed
     c.  Wireless AP is performing MAC address filtering
     d.  Sources of signal interference
     e.  Sources of signal attenuation

See Troubleshooting Microsoft Windows XP-based Wireless Networks in the Small Office or Home Office for details.

3.  General things you can try:
     a.  Recycle power on your wireless access point.
     b.  Check your laptop's TCP/IP configuration using "ipconfig /all" command from a command prompt window.
          (1)  Do you have an acceptable IP address, subnet mask, default gateway assigned to the wireless network adaptor?
          (2)  Is it set manually or dynamically via DHCP?
     c.  Use "ping" command from command prompt window to check connectivity.
          (1)  ping 127.0.0.1                    to test TCP/IP protocol stack.
          (2)  ping <laptop_ip_address>     to test connection to laptop adaptor.
          (3)  ping <default_gateway>       to test connection to another LAN node.
          (4)  ping 69.72.169.241              to test connect www.computerhope.com

[Moderator]

Try resetting the router (disconnect the router from the power source for a minute)

A couple things to add...Laptop does connect to someone elses network and laptop is used between work and home.It was connecting fine in the past for more than a year.

Do you encryption set up [WEP, WPA]?  If so turn it off within the router configuration and see if the laptop connects.  If it does then re-encrypt again and try.

Alan <><