This computer is an antique, so it has always been a bit slower than I am accustomed to, but it has gotten slower than before. I keep the programs to a minimum, and do regular spyware/adware removal as well as regular maintenance. Recently, however, my antivirus stopped working. Attempts to get it to work again brought up an error message (see photo) and working with Avast support elicited the information that there was a problem with my registry.
Have attached some screen shots that I am hoping will help in case I haven't described the issues well enough: