However, despite the symptoms seeming as though it's overheating, it isn't. It's impossible, it's only been turned on for 2 minutes. I think something may have became dislodged inside when I was demonstrating my 'over protective laptop bag' (which seemingly isn't that protective afterall!) and has perhaps disrupted the temperature sensor?

I have disassembled the laptop and tried clearing out the dust, re-connecting the processor etc, then re-assembling everything. The problem did not improve at all.

Before I take this to a computer repair shop (which I know will be expensive, and I do not currently have the cash to part with), I'd like to know if anyone else has had a similar problem, and if they know of a solution?

Thanks in advance