Everytime I click “Run”, the virus/worm pops up and won’t let me continue the process. HELP!
Does this virus/worm have a name?
Does it look like a security program? or do you mean a pop up from avast, can you post a screenshot?
Welcome to the forums, jholling. 
As Pondus indicates above, we need more information to be able to help you.
Please tell us all you can about your problem.
Do you mean you can’t install avast?
Which is your old antivirus? How did you uninstall it?