Glad you figured it out.

I was just throwing some ideas, I wasn't sure if they would work or not.

I was thinking something like this so sound only played once:

bool Play_Sound;


if ((latestlatestmain >= 0) && (latestmain < 0))
{
Play_Sound=true;
}

if (Play_Sound==true)
{
PlaySound("alert2.wav");
Play_sound=false;
}

Maybe?