False temperature reading

[Rebuild]

Hello!
First off my english is not great so please try to be clear with any instructions you may have. Also i will probably make some typos and whatnot.
Now the problem i have is false temperature reading and that causes every fan on my computer to go grazy. I checked temperature readings with both speedfan and HWmonitor(?)
Speedfan shows that everything is normal except temp1 which is maxed out at 99c and HWMotitor agreed. I been having this problem on and off for quite some time now and it is starting to piss me off. It seems to occur randomly at computer start up and goes away randomly at start up. I have tried to update bios, didn't help. Next thing i tried was to play around speedfan settings, that didn't seem to have any affect at all. Next i tried to adjust fan speeds manually from bios and i could not find any setting for that. All i did find was something that showed fan speeds so that was a dead end also. Now here is speedfans stuff copypasted:

Fan1: 4587RPM Cpu: 33C
Fan2: 3632RPM Local: 25C
Fan3: 0RPM Temp1: 99C
Fan4: 0RPM Temp2: 23C
HD0: 25C
Core 0: 27C
Core 1: 28C
Core 2: 28C
Core 3: 28C


This is a prebuild machine. Some hardware i have:
Intel i-7 2600 3.4 Ghz
8G ram
2TB Hard Drive
Lackluster GeForce GT 545


Like i said before my english is not that good and on top of that i'm not very good at this stuff so if you have any instructions please try to be as clear as possible.

 

[steddora]

Well the reading of that is quite odd, but since there is no RPM on the "fan" I'd imagine it's just an empty fan header from the motherboard. However, it seems Fan4 is reading a temperature that is more "normal". Are the fans always at max? Also, what is the make and model of the machine so we can better know what type of hardware we're looking at for the motherboard.

 

[Rebuild]

Well the reading of that is quite odd, but since there is no RPM on the "fan" I'd imagine it's just an empty fan header from the motherboard. However, it seems Fan4 is reading a temperature that is more "normal". Are the fans always at max? Also, what is the make and model of the machine so we can better know what type of hardware we're looking at for the motherboard.

Fan speeds adjust according to what i'm doing. Browsing and such i get around 1300RPM for both fans. Under stress i.e gaming i haven't checked but i'd guess it's around 2000RPM because it's nowhere near as loud as maxed out fans and that's what makes this problem so annoying. My computer is quite silent even when gaming but when the false reading occurs this thing is really loud.

This is the machine i have: http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03087787&lang=en&cc=us&taskId=130&contentType=SupportFAQ&prodSeriesId=5146418&prodTypeId=12454

 

[steddora]

Maybe it's just a bad sensor? I've had sensors fail and cause an erroneous value like that before. Hasn't happened to me in quite a while but it has happened.

 

[Rebuild]

I suppose it could be. Ok so how can i fix this?