Simaril, you said the computer runs cooler with the case on than with it off. If this is the case, I think something else needs to be done. I had an old Prescott chip that ran hot enough to fry eggs and bacon. Case on and case off, was just a matter of a few degrees depending on several variables. Point is, to get air blowing on your components. If case on or case off makes much of a difference, you need to rethink you system cooling components. This is why I said get a box fan, point that sucker strait onto your mobo, crank it up, get the room cool, around 70 degrees F should do, then play the game that makes the dots on your screen. If things run OK, then you can think about getting some cooling components. My gut is telling me you still have heat issues. Not blocked vents so much as it is, insufficient cooling for the components in your system. Also, dont forget on the video card, there is an intake as well as an exhaust. I have cleaned my card exhaust and the fan itself using compressed air, but forgot to clean the intake side of the card. It was 75% stopped up on that side.
