Here you go:
You can remove all of the files individually by bringing them up through Advanced. Search. Here's what you do:
From inside the Search pane on the Start menu, press F3.
That brings up the Search page - click the Advanced Search button to the far right to open the set up screen.
In the next screen check: the Include non-indexed, hidden, and system files option. Under Location, select Computer or Everywhere, and in the Name box, fill in AVR. (After the AVR search is completed do additional searches for any other key words you think might be associated with AVR files.)
Run the searches, and wait patiently while your hard drive chatters away. It could take 20 seconds or 20 minutes, depending on how much work there is to do, but you'll eventually see extensive search results that actually represent the files on your drive. You can delete each one of these files.
By the way, before you do the searches, you might want to take a look at your Program lists in your C:\ drive. Sometimes, even though a program isn't listed any more in Programs and Features, some or all of the files still remain listed in the Programs lists. Delete those, and be sure to delete any shortcuts to the Desktop and Taskbar.