I just bought my first Mac yesterday, i know there are many people waiting for the upgrades but i cant wait coz my summer is quite boring at home. The machine is i5 27'' However, the iMac is unstable and i think its because the operating system. Since this is my first mac and I'm not familiar with it, so i really don't know what is really the situation here. I just used it normally and the software i was using suddenly turned into no response and the pointer became the colorful spinning wheel. I tried click "force quit" but there is no response either. And i clicked other opened softwares, these softwares also turned into no response one after the other. Then I tried click the top left "apple" logo again to see if i can restart the mac but the spinning colorful wheel appeared and the menu just wont open anymore. However, the most interesting thing is the movie i opened at the beginning(i was "listening the movie and doing other stuff) was playing without any interruption, although i cant fast forward or pause it or close it or change the volume, but the movie was playing. The situation stated above was just happened couples of minutes ago. Last night i forced turn-off the mac 2 times coz the same situation. I really dont know why and how to solve it. The machine is new, so i don't think it can be this unstable. I don't have any experience on dealing with mac, so plz help me out here. PS is there any tool like "Task Manager" in PC for Mac? And can i open it through keyboard. Sorry for the poor English and Thx a lot! T H X!