Is Overclocking Safe for My Computer?

The short answer is no, overclocking isn't safe. However, chances are low that you will destroy your computer simply by overclocking it.
It is the heat, that may break your computer parts, especially the CPU. Running at high frequencies may cause the CPU to overheat, which may cause serious damage.

Having that said, get yourself a heatsink with powerful fan or have replacement parts at hand.