Most of us have been touched in some way by diseases such as cancer, Parkinson's and Alzheimer's. Seemingly daily, there's more grim news about food shortages and climate change.

But you can help make a difference and it doesn't cost you time or money.

Your home computer does the work. The idea is genius. When a problem is too complex for one computer to solve it in a timely manner, pieces are delved out among many computers. Each computer solves its portion of the problem. Then, results are sent back to a main server. This is called distributed computing.

Typically, distributed computing programs work as a screen saver, so they run when the computer is idle. To join a distributed computing project, you download a program. The program connects to a server to receive tasks and return data.

Distributed computing projects don't require particularly powerful computers. If yours was purchased in the past three or four years, it will probably work. You do need an Internet connection. But speed isn't important; many projects work with dial-up.

Here are a few popular projects to get you started. You will find links to these at www.komando.com/news.

FOLDING@HOME

Folding@home is run by the Pande Group, a lab that's part of Stanford University's departments of chemistry and structural biology and Stanford's medical center. Folding @home's goal is to understand why proteins "misfold." Protein misfolding can lead to diseases such as Alzheimer's, cancer and "mad cow."

It runs on Windows, Mac OS X and Linux as well as the Sony PlayStation 3 gaming console.

ROSETTA@HOME

The Baker Laboratory at the University of Washington runs Rosetta@home. Like Folding@home, Rosetta@home studies proteins. The project may lead to cures for AIDS, cancer and malaria, among other things.

Rosetta@home runs on Windows, Mac OS X and Linux.

WORLD COMMUNITY GRID

IBM sponsors the World Community Grid. It aims to create the world's largest public computing grid. It makes the resources available to nonprofit projects that benefit humanity.

The World Community Grid lets you choose from several different projects.

You can help study climate change. Or help farmers develop better rice strains. You can also study diseases such as cancer, AIDS, hepatitis C and West Nile.

The World Community Grid runs on Windows, Mac OS X and Linux.

CLIMATEPREDICTION.NET

Oxford University, Rutherford Appleton Laboratory and The Open University, all in the United Kingdom, run Climate prediction.net. Its goal is to improve climate modeling. This will help predict how climate may change in the next century.

www.Climateprediction.net runs on Windows, Mac OS X and Linux.

SETI@HOME

Want to help find ET? SETI@home is run by the Space Sciences Laboratory at the University of California, Berkeley.

The project downloads telescope data to your computer. The data is then analyzed for evidence of radio transmissions from extraterrestrial intelligence.

SETI@home runs on Windows, Mac OS X and Linux.

What about security?

Distributed computing projects only interact with its files and downloaded data. Additionally, data files are digitally signed.

This helps ensure that files have not been modified in transport. The program will reject files with an incorrect signature.

Because of the way these programs work, they should pose no security risk. So get started today and put your idle computer time to great use.