The Computer will not turn on
The computer will not power up.
The Power Button for the computer is located on the bottom housing to the right of the plug-in ports. Push the power button in order to turn on the system. If you do not get an immediate response, try holding down the power button for an extended period of time (10 seconds).
Check that the power cord is plugged into both the wall and the computer.
If the problem persists, try using other electrical outlets to verify that the problem is your computer and not the electrical outlet you are using.
The USB Mouse is Not Being Recognized
If your iMac isn't responding correctly to the mouse.
Check mouse connection
Unplug and replug the the mouse to the computer.
Check mouse surface
The best surface for the mouse to be on is a flat surface that is not transparent. Also, the surface should be plain and should not reflect light too much (like a mirror).
The computer is not responding
You can't get your computer to respond to your mouse or keyboard.
Make sure keyboard and mouse are connected
Try unplugging and re-plugging in devices, making sure the connection is secure.
Try to cancel whatever your computer is trying to do
Hold down the "Command" and "Option" keys, and press "Esc." This will force any open application to close. You can also close any open application by clicking the application on the icon toolbar and selecting "Force Quit."
Restart your iMac G4
Hold down the power button for about 5 seconds, and the computer should turn off. Press the power button again to turn it back on. If the problem persists, try completely unplugging and re-plugging in power cord from wall and rebooting.
Question Mark Flashes at Startup
If iMac G4 doesn't start up at all, hold "Option" key and restart computer.
Once computer is booted up, open "System Preferences," and click "Startup Disk." Select the local Mac OS X System folder.
If you cannot find the folder under "Startup Disk", you may have to insert the original OS X DVD that came with the computer (or order a new one if you no longer have it),and reinstall the system software of your iMac G4.
Cannot Get Wifi
Your iMac G4 cannot detect or connect to wireless connections.
Make sure it's your computer that has the problem
Try unplugging and re-plugging in your router.
If you have another wireless device, see if the internet can connect with the other wireless device.
If the problem persists, your computer settings might be the problem. The problem could also be the airport card.
Check to see if your iMac G4 is detecting your Airport Card
Click on apple in top left had corner of your screen and select "About This Mac".
After pop-up appears, click "More Info..." to open the System Profile.
On System Profile window, scroll down on left hand column. Click "Airport Card" under the Network tab.
If the right hand panel reads "No information found", your iMac G4 is not detecting the Airport Card, and it will need to be replaced.
If your iMac G4 is detecting the Airport Card, but you are still experiencing issues, there are several things you can try. See if you can locate your problem on this great link from the Apple website. http://support.apple.com/kb/HT4628?viewl...
Broken Airport Card
It is possible that your card is old...... needs to be replaced. Follow this guide to replace it.