A few Google searches turned up the following methods for re-enabling safe mode on XP.
From: http://www.p2pconsortium.com/index.php?showtopic=14474 I found this: Close all open programs. Click Start, Run and type MSCONFIG in the box and click OK The System Configuration Utility appears, On the BOOT.INI tab, Check the "/SAFEBOOT" option, and then click OK and Restart your computer when prompted. The computer restarts in Safe Mode. Perform the troubleshooting steps for which you are using Safe Mode. When you are finished with troubleshooting in Safe Mode, open MSCONFIG again, on the BOOT.INI tab, uncheck "/SAFEBOOT" and than click on the General tab & click the Button for Normal Startup than click OK to restart your computer.