Artifacts on screen after mouse clicks

Could be many things, we should start with this...

"Try Disk Utility

1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk."

http://docs.info.apple.com/article.html?artnum=106214

Then Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, reboot when it completes.

The usual reason why updates fail or mess things up, is if Permissions are not fixed before & after every update, with a reboot... you may get a partial update when the installer finds it doesn't have Permissions to change one obscure little part of the OS, leaving you with a mix of OS versions.

Some people get away without Repairing Permissions for years, some for only days.

If Permissions are wrong before applying an update, you could get mixed OS versions, if Directory is the slightest messed up, who knows!

If many Permission are repaired, or any Directory errors are found, you may need to re-apply some the latest/biggest updates.

May even need to do an Archive and Install if you have room on the HD...

http://docs.info.apple.com/article.html?artnum=107120

I only use Software Update to see what is needed, then get them for real via...

http://www.apple.com/support/downloads/

That way I can wait a week or so, check the forums for potential problems, and get Permissions & such in order before installing.

Hello,

Some info here: http://support.apple.com/kb/HT1721?viewlocale=en_US

Carolyn 🙂

I am having the same issues with my displays as you are.
With little block artifacts showing up on screen.
I am only having this issue with my recent install of Tiger.
I still have Panther on my G4 and the LCD panel works fine with no issues.
I repair permissions regularly during updates and installs, but haven't tried doing this from the the OS disk to see the problem can be fixed that way.
I am frustrated, too, but will let you know if I come across a fix.
It's annoying, but can still use my Mac until I or somebody else can come up with a solution. The 9600 is a listed minimum card for core image on OS 10.4, so I am not sure why it's doing this either.
I'll post back if I am able to solve this problem.

Success!!!!
Golfhacker, if you are still having issues with your monitor, you need to start up from the OS X Tiger install CD. When it boots, click the right arrow at the bottom of the window, the disc will begin setting up the installation.
Next, in the upper menu, click on utilities and run Disk Utility.
In the left pane, click on the drive icon that you use to boot into OS X Tiger.
On the lower right of the Disk Utility window, click repair. Once the repair is finished, on the lower left part of the Disk Utility display pane, click repair permissions.
Once this is done, go back to the upper menu, click on utilies, then click on startup disk and clicl on your normal OS X Tiger boot drive and click restart.

Once restarted to your original boot drive, before doing anything else, locate Disk Utility in your Applications folder under the Utilities folder.
Start Disk Utility and do another repair permissions.
This should clear up the issue. It did on my G4.
Hope you see this.