Will viruses in recycle bin be permanently deleted when recycle bin is emptied?

Viruses aren't really sent to the Recycle Bin; the files infected with viruses are sent there. So, even if an infected file is permanently deleted, it does not mean your computer is safe. Further, many sophisticated virus writers can make their malicious code resistant to deletion and can even propagate when the user tries to delete them. It's important to use a good anti-virus program -- there are more than several out there, including the free program, AVG -- almost all of which create a quarantine and provide safe, thorough removal.