You haven't indicated what operating system you are using or what version of Lightroom you have installed on your new computer. So it requires some second-guessing trying to tell you what you should do. The more information you can provide, the more likely it is that you will get reliable information. However, it sounds as if you have installed Lightroom and your images on the new computer as well as your catalog from before. You'll probably need to go to the library module and right-click on folders and update the folder location and point Lightroom to where the images are located now. Your images are probably located on a hard drive with a different name or different letter designation. If you have all of your folders within one master folder then you only need to update the location of the master folder and everything else will fall into place automatically. Here is a link to some information that might be helpful:
New computer is a Mac pro book running Mac OS Sierra, and then the monthly Adone CC plan, newest version. I think what you've suggested sounds like it should work- I just kept tripping up trying to find how to do it! Thanks so much! Really appreciate the help!
Hey again Jim, I clicked on the folders when in library mode and can't find an option to manually tell LR where the pictures are now located, I know I've come across the option before by accident and now I can't find it!!!