how to monitor temp?

HI There ; Do you find this message annoying? Why not make a post and get rid of it ?

[princee18]

I know there is software out there to monitor the temperatures of the internals (processor, mobo, etc.). Where do I get this software from? How do I find out what these temperatures are supposed to be?
If I do figure out that my computer is running too hot, how do I diagnose why? Is it true that this is dust 99% of the time? Thanks all.

[Xtreview]

I use speed fan .
Temperature will depend on the hardware used .
just let me know your computer hardware configuration so we can move further .