Answers:
A ribovirus is a virus that have RNA as its genome. HIV (not AIDS) is a ribovirus. AIDS is a syndrome cause by HIV.
A retrovirus is any virus belonging to the viral people Retroviridae. They are enveloped virus possessing a RNA genome, and replicate via a DNA intermediate. Retroviruses rely on the enzyme reverse transcriptase to act the reverse transcription of its genome from RNA into DNA, which can afterwards be integrated into the host's genome next to an integrase enzyme. The virus next replicates as portion of the cell's DNA.
http://en.wikipedia.org/wiki/retrovirus...
HIV (the virus that cause AIDS) is a retrovirus.
A ribovirus is a virus that have RNA as its DNA, which would include hiv (remember RNA genome?) , colds, etc.