Problems w/G4 Freezing

Hi All. First of all, I must confess that I am a PC user (please be gentle/patient/detailed in replying). However, I happen to work in a lab that uses MACs and am having quite some trouble with our G4 (as this is the only computer of any power for ~9 people, this poses quite a problem at times). In any case, for some reason the computer screen will flicker (almost like it's "blinking") several times and, more often than not, the system will freeze, requiring it to be reset. This is a chronic, recurring problem (to the point that people save their work every minute or so). I really have no idea what is going on (having never encountered such a situation before; my initial thoughts are bad HDD and/or RAM) and am rather hoping that you may be able to help. Many thanks in advance. Take care.

It's doubtful that this will help, but has the machine had the permissions repaired and all of the maintenance scripts run?

To repair the permissions, open the application called Disk Utility. Select the main HDD (startup disk), and click "First Aid", then on "Repair Disk Permissions".

To run the maintencance scripts, do the following (be sure to do it for all three daily, weekly, and monthly scripts):

1. Open the application "Terminal" (found in Applications/Utilities).
2. Type: sudo sh /etc/daily

Optionally, for Mac OS X 10.2 or later, you can use: sudo periodic daily

Typing daily runs tasks normally scheduled for a daily interval. Type monthly or weekly in place of daily to runs tasks scheduled for those intervals. Weekly tasks usually require a longer time to run than others.

3. Press Return.
4. Enter your Admin password when prompted, then press Return.
5. Quit Terminal when you have performed all three tasks.

Then restart the machine and see if it has helped at all.

First, zap the PRAM.
Restart an hold down the command + option + P + R keys until after the system chimes for the third time.

If you still hav the problem and…
If you are running OS X, I would guess that it is bad RAM.

If you are running OS 9 then it can be a bad extension or bad RAM. If it is OS 9, try starting up with the extensions off. Hold down on the shift key until the mac face appears. If that solves the problem then it is a bad or conflicting extension.

Good Luck.