Avira RegCleaner can removes all entries that were created by AntiVir products. In this way, it prepares your system for the installation of a new AntiVir version.
It basically lets you choose the registry keys to be scanned for specific words. At the end of a scan process, the software reports if any key were found. Its an easy-to-use tool that requires no installation.

The license of this software is Freeware, you can free download and free use this uninstaller software.