Have you changed any of the power management settings either in Windows or your laptop's BIOS setup? I ask because if you disable the CPU C4 function, this will cause the CPU to run at FULL POWER, which can cause the fan to run more frequently.
Check out this support document on HP's support site:
Also, check out this tech document about cleaning your PC:
It's possible that the fan vents have become dirty, preventing the fan from properly cooling the CPU.
Has this always been an issue with your laptop or did it just start happening?