So there are two basic ways to check the temperature of your system and this is either through the BIOS or using a software application that comes with your motherboard.

Not all motherboards are able to monitor CPU and motherboard temperature's but nowadays most motherboards should be able to.

You are also able to monitor fan speeds in rpm (revolution per minute) and sometimes alter them in order to keep your CPU running at a lower temperature and some motherboards even have a feature that allows you to specify in what temperature range you wish your CPU to run at.