car is overheating while idling and moving?is it the Thermostsat or water pump?

It sounds like a possible probable thing ,but there is the thermostat that could be stuck ,and won't open because its either clogged or not opening like its supposed to. What do you think about that ??.... Thank you for your response !!

I have checked the fans and have found them to be working . I honestly believe its the thermostat not opening and closing like its supposed to ..what do you think??... I don't believe or going it to be the water pump , because they leak and make a loud noise ,, what do you think ?? Thank you for your response !!!. X