Update the Operating System

• 1). Connect your computer to the network using your wireless card or an Ethernet cable.
  
  
• 2). Click on the "Apple" button in the upper-left corner of the screen.
  
  
• 3). Select "Apple Software Update."
  
  
• 4). Select any available updates and click "Install." The installation may take several minutes to complete. Restart your computer when prompted.
  
  
• 5). Repeat Steps 1 through 4 until you receive a message that "Your software is up to date." Click "Quit" and test your wireless connection.
  
  

Run Network Diagnostics

• 1). Unplug your Ethernet cable if connected.
  
  
• 2). Click the "Apple" icon in the upper-left corner of your screen and select "System Preferences."
  
  
• 3). Select "Network" to open the system's network preferences.
  
  
• 4). Click "Assist me."
  
  
• 5). Select "Diagnostics." The Network Diagnostics utility will open.
  
  
• 6). Follow the instructions to diagnose your connectivity issue, then test your connection.
  
  

Delete Saved Wireless Networks

• 1). Click the "Apple" button and select "System Preferences."
  
  
• 2). Select "Network."
  
  
• 3). Select "AirPort" and click the "Advanced" button.
  
  
• 4). Click the "AirPort" tab.
  
  
• 5). Select your wireless network and click the "-" (minus) button to delete it from the list of saved networks.
  
  
• 6). Click "OK" and close System Preferences.
  
  
• 7). Click the "AirPort" icon in the upper-right corner of the screen.
  
  
• 8). Select your network from the list of available wireless networks. Enter your network password if prompted.
  
  
• 9). Test your wireless connection.
  
  

Run Apple Hardware Test

• 1). Insert the system CD labeled "Mac OS X Install Disc 1."
  
  
• 2). Shut down the computer.
  
  
• 3). Turn the computer on and hold the "D" key until the "Apple Hardware Test" icon appears on your screen. The icon is a picture of a paper scroll, a computer monitor and a stick of memory (RAM).
  
  
• 4). Press "T" to perform basic hardware tests.
  
  
• 5). Check the lower-right corner of the screen for results. If any hardware issues are found, contact Apple support or another computer repair specialist.