I have been having freezing issues lately and am trying to diagnose what might be causing the problem, whether it's hardware or software, and what specifically might need to be fixed. The freezing tends to occur when running any program (Safari, iTunes, Photoshop, iChat etc.) for a duration of time. For example, when typing in the address bar of Safari, the cursor will stop blinking, the pointer will switch to the pinwheel, and stay hung up until I position the mouse over the dock or activate Expose, upon which it will complete the text I typed. This will repeat endlessly until I restart. Other symptoms are occasional blocks or lines of static across the screen, which usually clear up when I switch into Expose. I have read many articles and forum posts regarding the graphics card I have (NVIDIA GeForce 7300 GT) and how it is causing many users problems. However, I wanted to check and make sure it was a hardware issue before I spend money to get it fixed or upgraded. Any help would be much appreciated. Thanks.