The thing about temperatures is that there is no precise standard to go by as far as what is normal. While the CPU temperature you mention is not ideal, it may be within a range of temp to be expected for your rig's configuration and environment, but I can't say that it is, because your System Specs for that machine are not given. The starting point is established when all components are running optimally, clean and in the environment in which it will remain. When I asked about your temps, I was asking about more than the CPU, because all temps relate to each other, but in this instance, I was thinking most of the GPU temp. Once you know your usual temps, what you need to be alert for is any unexpected change. It is this change that makes it easier to diagnose a problem, and take the proper steps to handle them.
I am not attempting to discourage you from cleaning the computer, that would be foolish of me, but yet I'm not convinced that it will solve this particular problem. In my opinion, 4 months is a short time as far as necessary cleaning, unless the environment in which your computer operates is not ideal, such as being dusty, or laden with cat fur balls, children unreined, etc. Go ahead and clean it, but more importantly, establish a baseline of temps to serve as the starting point for future comparison. Note these temps not only for the CPU, but also the system, GPU, hard drives, RAM, and anything else that you might have available, and the room temperature in which they remain. With these in hand, routine checks of future temps will make you aware of any changes before they become critical, and may suggest the origin of the change. I would recommend a monitor that displays temps in the System Tray, like SpeedFan. I have it set to display the CPU temp, and I can check the rest of them by simply mousing over the tray icon.
There is a new WHQL Nvidia driver...if your card is Nvidia, which you might try, but if you do, I would use Ccleaner as I mentioned previously, to clear out any remaining pieces of the current or previous drivers installed first, to eliminate the possibility of a driver issue. With these things done, you will be able to make better decisions about this problem and any that may appear in the future. BTW, the temp that you mentioned for the CPU during game play are not as important as the GPU temp.