PC turns off after a few minutes of launching a game, whats the problem?

[kidgarrett]

Just a quick update... took the PC into the garden with my can of air - with the added outdoor light I could not only see dust around the CPU fan / heatsink but almost a matted material made up of compressed dust!!! So this really could not of helped. Removed all of the thick dust with a precision screwdriver, pulling it away carefully and blow dusted the rest of the MB and components.

fingers crossed...

Thanks again for everyone's help.

[ToGGoT]

Is it usually sat in the corner under a desk? Positioning it somewhere with better airflow will always help!