The supplier of CD-burning software agreed to pay $5.3m (£3.4m) in cash and stock for Napster's intellectual property, including domain name trademarks and its technological portfolio.
Under the deal, Roxio will not assume any of Napster's pending liabilities, the company said.
Earlier this month, Roxio agreed to acquire the bankrupt online music distributor if it could gain court approval.
The company did not provided any details of how it will use Napster's assets, only saying that it will announce its development plans in the coming months.
Once the high-flying startup of college student Shawn Fanning, Napster pioneered an Internet song-swapping service based on P2P technology. The online music company claimed over 60 million users at its height, but the service got knocked offline in 2001 following a prolonged battle with the music industry over copyright infringement claims.
German media company Bertelsmann broke ranks with the music industry by investing millions of dollars in Napster, in the hope of cashing in on a global audience of music fans keen to download tunes over the Net. In September, the bankruptcy court blocked the company from buying Napster.