Quick run through: Today my computer started acting up. This behavior first occurred when I was watching a youtube video and the computer screen just froze up/started blinking/exhibited weird patterns but the sound kept playing. This happened 3 times. Then I gave up and left the computer alone for a couple of hours. When I tried starting the computer again, it showed weird patterns again and completely refused to load up OS X. After that I've tried booting through OS X boot DVD Tried holding down: C (Nothing happened) D ( Got all the way to hardware test, the test said nothing was wrong. Tried the extended test, the computer froze up) option + command + P + R (this apparently erases RAM memory, this actually worked and the computer restarted, but I only got a different pattern and it still wouldn't load OSX) COMMAND + V (loaded up all the way until a message that said "warning audit space low(<5% free) on audit log file) After struggling with this for hours, now the computer suddenly works again. Everything seems to work normally, not sure for how long though. Thought I'd ask what could be the cause for this and is there anything I can do to prevent it from happening again. Initially I thought the graphic card was toast because of the weird patterns, but now it seems to work so I don't know? Plus why wouldn't it load up OSX just because The graphics card has some error? It's a 2008 iMac 3,06 Ghz 4Gb RAM 500 GB HD (19,61GB free) NVIDIA GeForce 8800 GS Also, if it starts acting up again and it is in fact a hardware failure (like it seems it is), does Apple cover the costs of maintenance for something like this? I'll attach some images.