The pressure group has built a large sculpture outside the CeBIT trade show in Hanover made of computer parts to highlight the issue of waste in IT.
Greenpeace waged a three-year campaign against HP after claiming that the company included high levels of brominated flame retardants in its PCs. It said that HP has agreed to phase out the chemicals by 2007.
"The motto for this year's CeBIT is 'digital solutions for work and life'," said Greenpeace toxics campaigner Martin Hojsík. "We want next year's motto to be 'digital solutions without pollution'."
"Although HP has been recycling for many years, the new free recycling service will be available for the first time throughout the entire European Union," said Kirstie McIntyre, WEEE programme manager for HP UK & Ireland.
"By offering the new one-stop service for free, HP is making it easy for businesses to use. Unlike the previous recycling programme, there are no calculations or negotiations regarding the volume and type of products being returned."
An HP spokesman told vnunet.com: "HP eliminated more than 95 per cent of the brominated flame retardants used in the external case parts of its products more than 10 years ago.
"During the same timeframe, the company also eliminated polyvinyl chloride from the external case parts of its products.
"Work continues on the identification of flame retardants to replace the remaining uses with alternatives that will not compromise product performance and will not present health or environmental risks."
Cotton seedling freezes to death as Chang'e-4 shuts down for the Moon's 14-day lunar night
Fortnite easily out-earns PUBG, Assassin's Creed Odyssey and Red Dead Redemption 2 in 2018
Meteor showers as a service will be visible for about 100 kilometres in all directions
Saturn's rings only formed in the past 100 million years, suggests analysis of Cassini space probe data
New findings contradict conventional belief that Saturn's rings were formed along with the planet about 4.5 billion years ago