CPU Heat problems hanging error in desktop computer, restart hota hai again , intel motherboard fan

changing cpufan of intel motherboard in my desktop computer. Want to clean CPU fan dust, how to open up cabinet or where CPU fan is installed,  hanging error in my old computer. service and repair by cleaning fan of motherhood in computer desktop.
heating problem is very common in electronics gadgets so don't worry be calm and keep patience. aap self engineer hain apne computer ke.