Hi there, Today i was using my iMac (24inch, intel core 2 duo, 3.06GHz processor, 2GB ram) after playing World of Warcraft for a couple of hours, i started watching youtube videos. Whilst watching a video i made it full screen in 1080p. After this the video started to lag and upon attempting to exit fullscreen the screen froze and presented a solid grey or blue colour. Upon restarting i was able to log on but 2 seconds after log in it goes back to the same frozen solid colour. I attempted logging in mutliple times and sometimes the colour changed to green. I can boot it up into safe mode and everything is fine with no problems running etc. Just wondering if anyone has experienced this problem before and could help me out with resolving the problem. I had something like this happen before but slightly differently after my graphics card burnt out. It happened a year after having my mac and i was unable to log on at all, the screen just flashed up with multiple colours, so i guess i'm ruling out graphic card problems? Thanks in advance for any support given. (It says in "About This Mac" that i'm running Mac OS X Version 10.5.8) Update: Just too help you out with a bit more info, i have tried verifying & repairing the hard drive, running a apple hardware test, and resetting the PRAM and SMC.