Wifi Networks and Default Applications

Resolved two issues today.  The first was that because my laptop was used by someone else before it was given to me, it had a lot of wifi networks in it.  I knew they were there, and many of them I'll probably not get anywhere near, but I don't want it jumping on the AT&T wifi network (for which I no longer have free access) without my telling it to.  I do, however, want it to get on networks I set up, and I couldn't figure out how to delete the networks I don't want it to use.  Part of me also just didn't want wifi networks I don't know and will never use in there...

I've looked at the Network console in System Preferences more than once.  If you open it and click on wifi and then on Advanced, you'll see a list of all of the networks that have been saved so far.  What I didn't notice was that there are a pair of buttons right below the list, one a plus sign, the other a minus sign.  Highlight one of the networks and click the minus sign, and it will delete the selected network.  Just be careful to select the one you want (although it does ask for confirmation).  I find this pair of buttons a little odd - there are other options for adding a network manually, including one that says 'Join Other Network...', so why isn't there a more obvious 'Delete Network' button?  I suppose I might have noticed it a little more quickly if I were more used to Mac.  Thanks to Joel, our IT guy, for that one.

The other issue I came across was that my PDFs were opening in Previewer.  Previewer is pretty cool, but it doesn't do a great job with PDFs if you need to zoom them (or PowerPoints with animations).  I found that if I user the Open With option on a PDF it would let me tell it to use Adobe Acrobat all the time, but that didn't seem to work even though I did it more than once.  At some point, I figured out that this change actually only applies to the file you selected, not to all files of that type.

So, since I really do want my PDFs to open in Acrobat, I did the highly specific search in Google for "default applications mac".  That is to say, I typed "default appli" and Google offered, among other things, "default applications mac", so I picked it.  The first option that came up was from MacWorld, and explains exactly how to do it...