Windows dialer question

I use windows dialer, hence the title of this thread, and would like to know if the following is a normal glitch; I was signed on earlier this afternoon and when I went to sign off I could not find my little connection icon in the system tray (the two computers). I right clicked the toolbar, clicked customize and the icon was not listed in the current or past icons list. I had to turn off the connection by ending the process in task manager. My main concern is that this could be some kind of bug, or worse, a trojan / virus. I ran Avast, Spybot, and AdAware directly after this occurence, found nothing, and have not had a problem since. Any information is greatly appreciated.