Sometimes Sygate Personal Firewall is missing from the system tray and device manager. I've never noticed when it goes, but it does. I thought this might be a virus or a trojan, but AVG Free comes up without anything.
this has happened to me too...i never did figure out what was wrong with it.....i figured it was a programming error cause i never had any virus turn up or anything either.
i use zone alarm now though and like it much much much better...i beleive there is a free version too if you don't want to pay money or don't believe in piracy....
Sygate Personal Firewall sometimes quits 
Linear Mode
