my hard disk temperature shows 51 celsius,is this too high?

i have hard disk thermometer 1.3 beta running in the taskbar and it shows my hdd temp is 51 which is classified as "warning" but not "critical"ie i can contnue working but with critical i should stop pronto.i tried to monitor my pentium d 920 and intel 945g mb with mother board monitor 5 but i coudnt get it to work.topala solutions siw also doenst record the cpu and mb temp.what could be wrong?i dont want to end up frying the motherboard or crash my hdd.
thank you in advance for your time and patience.