Thumb drives are handy little storage devices. They transport documents, picture files and the like. But they also can be used to run programs.

This portability allows you to use programs on a computer that doesn't have them installed. For example, you may love using Mozilla Firefox at home, but your office forbids installing it. You can bypass the problem by running Firefox at work from a thumb drive.

Portable programs also allow you to surf without leaving too many tracks. This is useful on a public computer, such as at a hotel or library.

Thumb drives range from $20 for a 128-megabyte unit to more than $600 for 8 gigabytes. Unless you need more room, look for 2GB or 4GB units. They provide a lot of storage and can be had for less than $100.

Here are four useful programs that will run on any storage device, even your MP3 player:

1. A free office suite. Imagine showing up to give a PowerPoint presentation, but the computer doesn't have the program. You can download a free viewer from Microsoft, but forget about last-second changes.

That's where Portable Open Office.org (www.portableapps.com) comes in. It's a free suite of programs that includes a word processor, spreadsheet, multimedia presentation program, drawing program and a database management program. All of the programs are compatible with Microsoft Word, Excel, PowerPoint, Visio and Access, as well as other programs such as Corel WordPerfect Office.

The suite requires 167MB.

2. A Web browser. Surfing the Net on a public computer is, well, public. Buying something online and failing to sign out could be dangerous. Clearing the browsing history and dumping the cookies and cache should erase your tracks. But what if you forget?

Portable Firefox (www.portableapps.com) allows you to surf the Net without leaving tracks. Extensions, bookmarks (a listing of favorite sites) and passwords used on your home computer can also be carried over.

The program uses 16.9MB.

3. All-in-one instant messaging program. Imagine talking simultaneously on Yahoo Messenger, AOL Instant Messenger and MSN Messenger. And using only one program.

Well, you can do it with Portable Gaim and Portable Miranda (both at www.portableapps.com). Portable Gaim is best suited for users who want to avoid settings. Miranda, although more complex, gives greater customization.

Portable Gaim requires 8.9MB of free space, and Portable Miranda, 1.2MB.

4. Password security. It seems like there's a user name and password for everything. Strong passwords require a combination of letters, symbols and numbers and are difficult to remember. And each account should have a different password.

The free KeePass (http://keepass.sourceforge.net) stores passwords in an encrypted database. It will import your list of passwords, or you can enter each user name and password manually.

KeePass uses less than 1MB.

Contact Kim Komando at gnstech@gns.gannett.com.