The average user doesn't care how or why, only that it gets fixed. And usually, whether they admit it or not (or even realize it or not), its usually the user's fault when something goes wrong. Which means they won't do the same stupid thing twice, or will at least hopefully remember how to fix it if they do.
In this case, I was messing around with settings in avast!, enabling/disabling processes and services, and in all ways just tinkering with things that are probably best left alone. I'm pretty sure something I did is what messed it up in the first place, but I'm not sure which exact thing I did caused it. I was unaware of the specific set of circumstances which could cause this problem, and thus left my tinkering out of it so we could all consider all possibilities.
All that aside, I mentioned 'go for the simple stuff first' idea because when I suggested an idea, it was ignored. I often find myself doing this; when we are presented with a problem, we dig up or hear in conversation one possible cause, then stick with that hypothesis and exclude others for longer than is usually good. In this case, everyone zero-ed in on conflicts with other AV programs, while no one really mentioned other possibilities (except igor).
I'm not trying to attack you guys, and what I'm saying is only partially fair- you really weren't going off on one thing for all that long. It was just an observation, particularly when I suggested safe mode and no one commented one way or another on that idea.
By the way, you all deserve some serious brownie points for the speed with which you responded to this- I'm used to posting something and checking back in a few hours, and its not unusual to wait a few days before getting an answer. Apparently, this forum is different. Good work!