Norton 2011 internet security deleted all my programs when I downloaded it

I replaced norton 360 2010 with norton internet security 2011 on 3 computers.  The first one and the last one I downloaded it from a disc to did fine.  The second laptop i put it on went through uninstalling the 360 and it also lost all my connections to the internet and all program files were missing.  I found some of them still on the hard drive but am having difficulty setting things back right.  I dont know much about computers anyway.  Luckily it didnt delete some important excel stuff I had on there but, everything else that we try to do is screwed up!!! I need help.