High temperature alarm on HD

Hi, I have a harddisk control program HDD Control2 (Guard) running on my laptop. Today at startup 9:30am I got the message: Temperature 19 °C Good - this hard drive is obviously cooled very well.
Now at 20:15 I got the message: Temperature 51°C Bad - You should think about cooling you hard drive better.
Further: Health 100%
Performance 100%
Sometimes, at heavy load,I think, I get even the treshold alarm of 52 °C together with a noisy audible signal and an even more severe warning message. Then I switch the pc to standby for a while.

The computer works good and fast always until now (hardware). Do I really have to undertake some protective measures? Internal cleaning of the computer and cpu-fan and/or getting some kind of so called laptop cooler stand. I wonder if this is really so critical, I have the computer since 2009 and the guard is installed only a couple of month and now I switched off the guard option, so I get no alarms any more.

performance benchmarks:
read perf. : 49,10 MB/sec
min: : 26,14 MB/sec
max : 67,95 MB/sec
accesstime: 32,89 ms

Hello cleaning your computer is important I live in Arizona and clean mine every 60 days by vacuming all the dust and dirt. I remove my fans and vacume under them and cleaning all around my fans etc. always a good practice, to much dust and dirt on you fans can lead to overheating...

Overheating may be the most serious problem that your computer will face. If you follow the information in this aritcle the problems may be avoided.
Learn something – How to clean your laptop to solve overheating problems – The Blogs at HowStuffWorks
Try to download and use speccy to determine the tempertures that are inside your computer.
http://download.cnet.com/Speccy/3000-2094_4-75181811.html
You may also want to test your hard drive
http://pcsupport.about.com/od/toolsofthetrade/tp/tophddiag.htm