Is my computer now too old for OW? FPS < 15 during game play :(

The components you listed still meets the Recommended System Requirements for Overwatch. However you do not have a graphics card listed. Can you please specify that?

In addition check out this starting troubleshooting guide for tips on resolving most common issues with FPS performance:

I also have a Maximizing Performance for Overwatch guide which is helpful for getting the best possible performance when playing: