Most of the time, with desktops and laptops, temperature increase is caused by two things.
1) Fan/cooling system has broke/not functioning properly
2) Build up of residue preventing air getting in and out.
Number two is relatively easy to fix. Simply take the panel off your computer and spray some pressurised air in it (i.e [
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do not blow the dust off by mouth! Attempting to blow the dust off using your mouth will almost certainly mean some condensation/water will pass to your circuit board, which may cause future problems.
If you try number two, and it's still not fixed, check your computer fans that are cooling the system. If they are not rotating, or rotating as fast as they should be, there is obviously something wrong. It is best to check how the fans are operating by removing the panel like you would for problem two, and observing the fan and if it's moving fast enough or at all, rather than say for instance, putting a pen in and making the fan stop/brake.
If it turns out your fan is broke, you can pick one up at any good computer store for a fair price and install it easily. I would however recommend that if you have no knowledge of computers that you ask an expert to do it for you.
Also, to note the temperatures you posted seem normal enough to me, so it seems like there's no immediate problems to note.
/AC