please help

I am sorry if this question has been asked before, I couldnot find any answer that pertains to my situation.
I have an hp desktop, running Windows XP media center.
Play back sound is well, Microphone usage to record doesnot work. I have installed realtek HD driver, checked the drivers in properties, everything is working proper as per Windows yet I am not able to record my voice using the mic, used front and back jack slots, no effect....is this sound card problem?
thanks for help

 

It might be that the record volume/microphone sensitivity is low, or simply that the mic is broken?

 

Thanks Rik_NA, the mic is not broken, bought a new one, I think the problem is software conflict, I had installed Nero...I think that has caused some problems.
But thank you for your response.