My processor fan keeps coming on?

[nen29]

My processor fan keeps coming on?
I just cleaned my processor fan ang heat sink as it was clogged with dust. After i put everything back together the processor fan is coming on every 10-20 minutes or more if the computer is used. It is even coming on during the start up process. This did not happen before cleaning. Is there any chance that i will need to replace the termal paste or have i done something else wrong?

 

[evongugg]

Normally your processor fan should spin 100% of the time.
You probably have something in the Bios controlling the fan.
I don't see anything wrong as long as it spins. But 10-20 minutes before spinning looks excessive to me.
Check your temperatures in the Bios and report back to us.

 

[sirheck]

If you removed the cooler from the CPU to clean it then you need to clean off the old paste and apply new paste otherwise the CPU will overheat.

it wont overheat.
it will only run a little hotter.

 

[sirheck]

your cpu fan should be spinning all the time.

maybe slower if you have q/c or speedstep enabled.
depending on which brand of cpu you have.

it should never stop spinning.