Missfix, the earlier Dell models like the XPS T had an option in the BIOS that enabled the Boot Time Diagnostic Screens. With this option enabled you could view the boot up process as the BIOS loaded. On the newer Dell systems like the 2400 this boot option is no longer available in the BIOS Setup so you are stuck seeing the Dell logo.
To find out, you can disable the splash screen by making a small change to the Boot.ini file. Follow these steps: Press Windows>>Break to open the System Properties dialog box. On the Advanced tab, click the Settings button in the Startup And Recovery section. In the Startup And Recovery dialog box, select the Edit button in the System Startup section. The Boot.ini file will open in Notepad; locate the line that ends with the /fastdetect switch. Position your cursor right after the parameter, press the spacebar, and add the /SOS switch. Save the Boot.ini file, and close Notepad. Click Cancel to close both the Startup And Recovery dialog box and the System Properties dialog box. Restart the system. When the system restarts, the splash screen will no longer appear. You can observe some of the operations that Windows XP performs during the startup stage.
To revive the splash screen, simply repeat the above steps to edit the Boot.ini file and remove the /SOS switch.