2003 Focus Stalling Problems

Hi I'm new here and having some problems with my focus I'm hoping someone can help me with. About a month or so ago it started cutting off while I was driving. My dashboard lights would all flash on and the car would shut down for no reason. I managed to pull over and restart, and it would run fine for a while, then happen again. I took it to a mechanic who checked it and did a tune up, and changed the fuel filter and I also had the oil changed. I thought everything was fine until about a week ago after a snowstorm when it started again. I took it to another mechanic who did a diagnostic on it and was told the problem was the idle sensor. I just got it replaced and thankfully it hasn't completely stalled on me while driving again just yet but my dashboard lights still flash and my cd player/radio shut off when I went to park so I am concerned that it is going to cut off on me again at some point. This is so aggravating and I was hoping replacing the sensor would take care of it, but something tells me it hasn't and I can't keep spending money trying to fix this. Anyone have any ideas on what might cause this? I was wondering if it had something to do with the battery since there is corrosion on one of the terminals, but I was told that couldn't be the problem since it starts right back up every time. I also had the key cylinder replaced shortly before this started happening because of problems with the key not turning and now have trouble getting it out when I shut it off and wonder if that was installed properly and if it has anything to do with this. I just have no idea. Thanks in advance for your help.