Your default web browser in Windows is the one that opens any time you click a link to open a web page, open an HTML file, or take any other number of actions that would require a browser to load. It's typically pretty easy to make a browser your default. When you run Internet Explorer, Firefox, Google Chrome, or Opera for the first time, odds are the browser will ask if you want to make it your default.

Things get a little more tricky when you start using portable browsers. These are browser that you can run without actually installing them to your computer. They don't write any data to your registry and all the files tend to be contained within a single folder which you can run from your hard drive, or a removable USB Flash drive or other media. One of the most popular is Firefox Portable.

But since Firefox Portable doesn't write anything to your registry, it doesn't ask if you want to make it your default browser. That's where a little freeware tool called DefaultBrowser comes in.

We first covered this tool a couple of years ago, when it allowed you to quickly and select your default browser from a small list of web browsers. But as the folks at Freeware Genius recently noticed, DefaultBrowser added support for Firefox Portable last year. That means all you have to do to set Firefox Portable as your default is download DefaultBrowser, run it once, click Firefox Portable, and hit "apply."

You can also select other portable browsers or any web browser not included in the DefaultBrowser by selecting pretty much any executable file using the "select your web browser" setting.

If you run Firefox Portable from a USB flash drive, if the drive letter changes you will have to register the program again.