Wireless-G LinkSys Model WAP54G random Internet... (by 3 users)

I have 30 computers hooked up to this system. Each computer has a separate external wireless card plugged into the USB port (from Dell). We are hooked to the school Novel network system

I have random access to the Internet at times which means a random 1-6 of the 30 computers are not connecting to the Internet. I've tried resetting the Internet hookup on the task bar, unplugging and replugging the wireless card and/or wireless G Access Point and sometimes this works. Sometimes resetting the computer will work.

I currently have 5 computers that will not connect to the Internet (not random).

Are there any other tricks I can do that don't involve our tech people so I can receive immediate access? I have 30 students in each class and we rotate every 42 minutes so, as you can see, time is of the essence.

Thanks!