My iMac (late 2009) has been crashing randomly every couple of weeks (sometimes more oftern) for possibly up to a year now. It's a weird crash... it just stops, as in I'll be doing something random (eg: from searching the web to Photoshop) and the whole computer will stop responding. I can't change desktop, I can't click anything, the beachball doesn't even show up. It just stops. The music keeps playing until the end of the song, then that stops too. I have to hold the power button and then start up again to recover it - loosing all my unsaved stuff.
It had a hard drive failure last week. I figured this problem was probably related, so when the HD was replaced (on Tuesday) I figured the problem would be fixed. I started afresh, no backup restored.
However, today I was using Safari and my computer froze the same way as before. So knowing it's not the HD, why is my computer failing? I get no error messages, and sometimes the computer freezes when I'm doing really non-memory-hogging things.
I have 2x 2GB extra RAM (from the Apple online store, just over 1 year ago) which I asked the guys at the Apple store to check out when I had the HD replaced, but they said they were good. The Apple store also ran a 'long diagnostic check' on the Mac, and said it was all good after the HD replacement, just 4 days ago. I have hardly any apps installed, and only CandyBar installed from outside the App Store.
Does anyone know what's up? It's driving me mad!
... I also didn't have the backup drive plugged in ever before when the computer crashed.
Thanks; I had interpreted the opposite.
BDAqua's suggestions still remain - Safe Boot, and add to the list creating a temporary account to isolate user-specific problems: Isolating an issue by using another user account
CandyBar should be considered suspicious as well - read: http://www.panic.com/blog/2012/08/candybar-mountain-lion-and-beyond/
I don't know how it does what it does. It's obviously a system modification and as such, has unknown potential effects. Such system hacks often do not survive a simple OS X update and it's clear the developer is aware that it could cause problems. When in doubt, remove such things.