ATI graphics card problem

I have the latest driver for my graphics card (9.1), and I often update the rest of my components.

My problem is that my graphics card heats a 85 ° C on the desktop, and up to 105 ° C in full screen 3D application, beyond my PC crashes and restarts as a major. Now to play a game "recent" I have to launch into a window, which is quite uncomfortable and all games have not this option (eg Call of Duty 4: Modern Warfare).
My graphics card does not heat, in short this happiness has totally changed. In other words, when I launch a 3D application, after a while (very short: 3min) screen and sound freezes. I saw once, who left the game before it crashes on the desktop I had an error message on the ATIKMDAG, I have no idea what it is ?
Why is my PC I like it for 2 months when I have changed any components?

I think it's your GC which is overheating, the 2900 is not known for their freshness if you know what I mean. If this is not the case that may come your thermal paste is to change, and if the problem persists invested in a rad adaptable as a zalman vf -900 or 1000 for example.

Thermaltake TMG AT2 CL-G0086 HR03-R600-specially designed for HD 2900 and very good cooling. Only problem is that it is a bit expensive