I have a very frustrating problem with my biege PowerMac G3 300mhz desktop with Apple 17" monitor running 8.6. Out of the blue, the computer now boots up and once it comes to the desktop, none of the extension icons or the Mac OS welcome screen disappear. The screen remains grey and can't change to a different theme. What's worse is that all succeeding windows that are open remain on the desktop when they are closed too. All of the finder icons "jump" to the front of any window they were behind when they are closed, creating a sort of snapshot picture set for the background. Eventually this fills the entire screen with former windows, very annoying.
I have tried resetting and replacing both the PRAM and the video memory with no luck. I unhooked the current monitor from the computer to a different monitor and the problem remains. I reconnected all internal cables and cleaned the insides. Even reset the "little button" indide. Rebuilt the desktop, zapped pram, started without extensions on and went through an exhaustive search of the extensions and control panels. Also threw away all monitor preferences. Nothing has worked except changing the resolution, number of colors for the screen, but after a while the windows really start to add up again.
Also, under the appearance control panel, the built-in desktops for the system won't load, but placed pictures will. This leads me to believe it has something to with the appearance control panel. Any advice or help would be greatly appreciated. Thanks.