Unfortunately, this factor is overlooked more frequently than a dwarf at a NBA player's convention. If your PC gets too hot, it will eventually fail. The symptoms are usually very weird and unpredictable. Not so good either, I bet. In the last few months I've worked on several PCs that had potential heat issues and I felt compelled to write a few lines about it to save others the headaches of running into heat problems.
Heat can come from external and internal sources.
Let's take a look at those different heat sources, identify them and see what can be done to eliminate the problem. Then move it. That pale beige color of the case is natural and won't tan no matter how long it sits in the sun. Move the PC into a spot where it is safe from sun rays. Then move it.