The screensaver doesn't cost you anything, and at least you're taking part in something, adding your bit

Professor Graham Richards

A coalition of scientists and technology companies hopes to speed up the search by recruiting the spare capacity of thousands of home PCs.

Similar schemes have been launched to hunt for extraterrestrial life and for new treatments for cancer.

At any one time, the average personal computer uses just 13-18% of its full processing power.

A technique known as peer-to-peer technology makes it possible for the spare capacity of millions of computers to be combined in a massive joint effort.

Screensaver

Participants download a screen-saver that runs whenever their computers have resources to spare, and uses that power to perform computations for the project.

Professor Graham Richards heads the research

When the user connects to the internet, the computer sends data back to a central hub and gets another assignment.

The company that designed the program, United Devices Inc. of Austin, Texas, US, promises that no personal information on participants' PCs can be compromised while they take part.

Professor Graham Richards, from Oxford University, UK, is leading the study.

He said that with enough participants, the project would provide researchers 10 times more power than the world's best supercomputer.

"The screensaver doesn't cost you anything, and at least you're taking part in something, adding your bit.

"Massively distributed computing provides efficient and speedy ways to identify new drug candidates.

"Particularly with anthrax and other related bioterrorist threats, speed to discovery is of the essence.

"Without this technology and the support of our collaborators, there would be no other way to tackle such a tremendous task."

The anthrax toxin is made up of three proteins that are not toxic on their own but become toxic after binding together.

Cancer search

The Oxford scientists want to scan 3.5 billion molecular compounds to see if any can block the process and keep the toxin from reproducing.

The results, which could serve as blueprints for late-stage anthrax drugs, will be given to the UK and US governments.

Professor Richards launched a similar project last year to help find a molecule to block the development of leukaemia.

It is harnessing the power of 1.3 million PCs around the world.