Scientists have thought that magmas that form new crust at fast-spreading ridges rise up from the depths, quickly crystallize, and then push away from the ridge to form new ocean floor.
To stop a computer from overheating never keep a cloth or something else on the CPU or monitor. Also use the save energy option from properties so as to switch off the monitor when not in use. This will always help in keeping the computer cool and not overheating it.
Taking the cover off will cut off the airflow path and cause your computer to overheat MORE. You can check your fans by simply taking the side off momentarily and see if the are spinning and feel for air, then putting the side back on. Again, DON'T leave the side panel off this messes up the airflow within the unit!