CPU temp at 47-50 C constantly

Hello,

In the recent days I have encountered a problem with my custom made PC. At first I could smell something weird and it was just dust. So I cleaned with a compressed air can all the dust off and started the computer. Once entered Windows my CPU fan just went spinning at 2400 RPM and it was quite loud compared to how it was before. I downloaded some software and 3 different programs were telling me the same thing. CPU temperature at 50 degrees Celsius. I dont quite know what the average temperature should be but given that the CPU fan started to spin at max and is constantly at max rpm, this tells me something is wrong. I went to the store bought some thermal paste and replaced the thermal paste on the CPU but it still spins at max rpm. Could someone help please?
 
So are you telling me that it is 50 while idling? If that is the case, then something is wrong. It could be that you are getting high voltages for some reason. I don't know what component controls this but maybe that is faulty. The only other thing I can think of is background processes or a virus.