What to do if computer hangs or reboots frequently. This can be a problem if the cooling fan connected to the CPU of the computer does not turn on or cool down enough. In that case, turn off the power of the computer, open the casing, check the cooling fan well and install a new cooling fan if necessary. You also need to check if the casing fan on the back of your CPU rotates while the computer is running. Even if the computer has a virus, such problems can occur. So every drive on the computer's hard disk drive needs to be cleaned by an upgraded antivirus. It can also be caused by loading new software or programs. In that case the program can be seen by uninstalling.