Hi newcomer and welcome to the Tom's hardware forum.
Yo need be more specific with your question.
1- If you want to know the temperature that your CPU have when is in use, you can use some programs like
coretemp,
HWmonitor or
speedfan. All support Win 7, Vista or XP.
2- If you want know the max temp that you processor can support, go to the manufacturer's processor web page, and you can find that information.