PC Internal Temperature

My PC, a Dell Dimension 8300, doesn't seem to have any internal temperature sensors - at least I can't find any reference or settings.

I'm therefore looking for a simple and/or cheap way of adding a couple of sensors to the inside of the case. I don't think I have any problems with the machine, for the last two years it's been running 24/7 and usually at 100% processor usage, but I'd like an advance warning of dust build up.

Any suggestions or recommendations please.

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Ian

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