Getting low number of bars when it should be high, or getting errors trying to join a network it should have no problem with?

Here are some things to try when Airport seems to not be connecting well.

1. Go to System Preferences
Click on “Network” (under “Internet & Network” in 10.4 & 10.5, under Internet & Wireless in 10.6).
Select “AirPort” from the column on the left.
Click on the Advanced but in the lower right.
Be sure you are in the “Airport” Tab, then select the name of the network you are having trouble connecting with from the list. Click on the “-” (minus) sign to throw it out. Click “OK” in the lower right.
Close System Preferences, and restart the computer.

2. You might want also to reset the Parameter RAM (PRAM) at the same time. Do this by holding down CMD & OPTION & P & R all at the same time as soon as you restart. Let the computer “bong” (startup tone) for three times. This resets a number of system parameters. (The

3. If these tricks don’t continue to work, then some other solutions might be needed. These might include re-installing the system software, upgrading the operating system, or reseating the AirPort card, or trying a different AirPort card. Let me know if it’s still not behaving.