Sounds like a possible heat problem assuming that you have your AC plugged in and are not running on battery which you did not specify.

[quote|holiver]Sounds like a possible heat problem assuming that you have your AC plugged in and are not running on battery which you did not specify.[/quote]

If you want to check your heat monitors (one could be going bad), get the FREE app, iStat, here at: http://www.versiontracker.com/dyn/morein...

My 17" G4 kept shutting down unexpectedly and when I used iStat, I saw the "heat" on one of the (5) heat monitors shoot up to some absurdly high heat just before the laptop shut down (actually, it seems it was doing a sleep, but whatever -- screen went dark.)

Try iStat, keep an eye on it for a bit and see if one of your heat monitors is erratic. When I found which monitor had failed, I googled instructions on how to fix it myself (just removed it entirely) and the 17" is working great now.

[quote|emil]If you want to check your heat monitors (one could be going bad), get the FREE app, iStat, here at: http://www.versiontracker.com/dyn/moreinfo/macosx/27037 My 17" G4 kept shutting down unexpectedly and when I used iStat, I saw the "heat" on one of the (5) heat monitors shoot up to some absurdly high heat just before the laptop shut down (actually, it seems it was doing a sleep, but whatever -- screen went dark.) Try iStat, keep an eye on it for a bit and see if one of your heat monitors is erratic. When I found which monitor had failed, I googled instructions on how to fix it myself (just removed it entirely) and the 17" is working great now.[/quote]

There was some power supply problems with imac g5.. faulty power supplies...lots of info here:

http://forums.macosxhints.com/archive/in...-44705.html

http://jimwarholic.com/2008/11/apple-imac-g5-power-supply-issues-and.php

[quote|Rich]There was some power supply problems with imac g5.. faulty power supplies...lots of info here: http://forums.macosxhints.com/archive/index.php/t-44705.html http://jimwarholic.com/2008/11/apple-imac-g5-power-supply-issues-and.php[/quote]

What do you mean

"it'll run for a while then just shutdown."

Will it run for a few minutes, a few hours, a few days? What are you doing when it shuts down?

Other solutions could be: "secured virtual memory" problem'' (uncheck it)''

Not enough free space on the HD

FileVault acting up

N.

[quote|machead3]'''What do you mean''' ''"it'll run for a while then just shutdown."'' Will it run for a few minutes, a few hours, a few days? ''What are you doing when it shuts down?'' Other solutions could be:''' "secured virtual memory" problem''''' (uncheck it)'' Not enough free space on the HD FileVault acting up N.[/quote]