The licensing conditions specify one licence allows installation on a single computer - for 5 computers you must purchase 5 licences - see section 1 of the EULA here.
To be a little less diplomatic than John if you have activated the same license on 4 computers and are now trying for a fifth, you have not only ripped off the company, but have violated the license agreement in many if not all countries. If this is what you have actually done, you have basically pirated software licenses. Consider yourself lucky that you managed to do this and have not been sued or have had all your licenses deactivated. Just buy a fifth license or let it go!
If this is what you have done, please know, that to me software piracy is the scourge of the earth. It cost real paid users more in software prices and is no good for any honest user. If this is not what you meant and have a different explanation of what you have done with your other 4 systems, please explain exactly what you, have done and accept my apologies. If you provide a reasonable explanation that does not include SW piracy, I will delete this post.
sorry gandjcarr (ripped off ) i looked at this n rotfled. funny you say that I thought the same thing when i bought MM 2013 AND 2014 PREMIUM same program diffrent names and really if you trail MM products you will see that there all copy of copy of copy for the most part and yea Ill will point out they removed the visual effects editor Becasue I contacted support they wouldnt even tell me what the last program was that had this feature... Anyway the proof was in the fine print on the advertisment page they really havnet done nothing with there products in the last 2 yers just renamed to make it seem new