Help! Where did my LR go??

Two days ago, while uploading some photos to LR, I noticed the program acting strangely, and working slowly.  Next thing I knew, I could not access LR, and continually get the "Welcome to Adobe Photoshop Lightroom " popup, and then it asks my country/region...  then it asks my registration number, which I can't find.  I do still have the disc, and the redemption code number, but can't understand what has happened!  I have uploaded Malwarebytes, and ran it but it found nothing.  Otherwise, my antivirus is adequate.  HELP, PLEASE????