Help - All my ADOBE CS6 programs are gone!!!

I have Adobe Creative Suite 6.  As well AS Premiere PRO and Lightroom.  I have not used them in months.  Today when I went to start a new project they are all gone.  I went to reinstall them and I get a invalid serial number.  But not true.  I have the original boxes and the serial numbers.  Why is this happening and what can I do to correct this problem.