Realtek Sound Card Problem. (Please Help!)

Hello, I had this odd problem today earlier today I was playing Counter-Strike 1.6 and I was talking on my mic and then all of a sudden my mic was muted so I go and check and make sure my mic is plugged in and it is then I make sure it’s plugged in the right spot it is. So then I go to my Realtek Sound Settings to make sure I didn’t accidently mute my mic but I didn’t then I asked some people over at AMXModX.Org and a guy told me it might be my Sound Card it might be "fritz"ing I have no clue what that is I tried rebooting my computer unistalling and installing it over again but it doesn’t work.Also when I was watching some videos on Google it did the same thing to me there was no music playing so then I reboot my computer and the sound works again but before that I tried playing a song on Limewire and it worked so i’m not sure what is wrong but I would love it if someone could tell me what I could do thanks.