I fixed the echo!
You see, I've been having all kinds of computer issues for the longest time now. First of all the sound went on the old computer - didn't have any at all for quite some time and it was most annoying!
Then I got the new computer and it turns out that what was worse than no sound, was this incredible echo issuing out of the new speakers I bought along with the new computer. Music wasn't too bad, but I couldn't hear a damn thing when it came to anyone talking due to the overwhelming echo. I played around a bit but nothing seemed to work.
Then this morning, while still suffering from this Really Nasty Cold, I decided to see if I could get it to go away - the echo, not the cold. Although I'd love the cold to go away too!
And I found what the problem was - I had the sub woofer going. Now I only have the vaguest sense of what that was and what it does, but when I turned it off - no echo!!