BleepingComputer.com: Sound card or Mic problem

Hi there, i wasn't to sure to post this in internal or external hardware problems because it could be either one. So here's the problem. One day i was on ventrilo (for those of you who don't know its program to talk to one or multiple people with over a server) and everyone was like "who has that terrible echo it hurts", so after figuring out that it was me i wondered what was wrong so i tested all the options in vent. but nothing has worked so i tried testing using the monitor in vent and what it dose is monitor all the sound that would go out to ppl and use number values for the level of sound (higher the number the louder the outbound sound is). after no results of that was going on I decided to try something, i unplugged my mic cable and played some music (it seams people can hear any sound from games too they can still hear me but every other sound it really loud) and tested it again and the numbers just go wild. so i have no clue how that's happening , if anyone has any advice or if you need any more info just post.

any help is much appreciated

Thanks