DefaultBrowser allows you set the default web browser for your user profile in Windows XP, without affecting the other users. The list of browsers you see in the Presets are tested and working flawlessly as user defaults. Note that the user interface in Windows XP does not provide an option for setting the default browser for each user.

• This utility is designed for Windows® XP systems only.
• Non-install .exe file.
• Requirements
  • Administrator or Limited User account. Does not work under Guest account.
  • To successfully apply the per-user setting, choose No when your Web browser prompts to make itself the default
• Undo the configuration by clicking the Reset button.

Get it at Ramesh's site:
http://windowsxp.mvps.org/defaultbrowser.htm

Currently these browser can be set default:

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