Danger to laptop due to fan malfunction even with cooling pad?
Your laptop is designed so that the internal fan provides a specific airflow for cooling.  Laptop designers know that internal fans will fail eventually and so it's unlikely that anything terribly bad will happen if the fan stops working altogether, but it won't be good for the machine - it may slow down to reduce power or perhaps shut down completely if it overheats.  An external cooler will certainly help but it's not a replacement for the internal fan.  It may be worth getting the internal fan replaced as it's quite an important part of the machine.