Activation Question

  Does a PC have to stay connected to the internet, for NIS 2011 to work?  Last night I connected a stand alone PC to the internet, downloaded and installed a clean copy of NIS 2011 to that PC.  I then used one of my activation keys, to activate the program.  When I went into My Documents and checked the Norton Internet Security_Key, it had the correct key listed.  I even ran a quick scan last night, with no problems.  Today after I removed that PC from the internet and moved the PC back to another room, I get a red "X" note saying the program needs to be activated?  Does this mean I can't run Norton's even for a day, without being connected to the Internet?  Another question, when I finished installing the program last night, the program showed the correct number of days remaining.  Today, since it is showing I need to activate the program, it shows I have "0" days remaining?