Can you use AVG with AntiVir or ANtivir with Avast or AVG with Avast or Antivir with AVG together. Can you use any of these free virus scanners at the same time and if so which ones, specifically.
If you mean do scans at the same time, I've never tried that because I think there would be a conflict with the resources.
However, if you mean have more than one active at the same time, I'm doing that now with AVG and Norton. I've not had any problems with running both of them, and they work well together (which IMO is due to AVGs ability to work with other AVs).