Old Ibooks dropping wireless connection

I work at a school that has several generations of Ibooks. Some of the Ibooks that were purchased in 2002 and 2003 have been dropping off the network. They are running OS 10.2.8. The airport signal has three to four bars lit on it so I know they are getting a strong signal but users still get errors about not being able to access the internet and not being able to print on our printers that are connected via Rendezvous.

I am fairly new to this position and am not sure how to go about troubleshooting it. So any help would be appreciated.

Make sure you have all the latest system updates installed (there were several updates to the Airport networking) and perform the usual maintenance tasks.