When the OS Choices menu appears at startup, you see the following message at the bottom of the screen:
For troubleshooting and advanced startup options for Windows, press F8.
If you have only one operating system installed on your computer, the OS Choices menu won’t appear. To display the Advanced Options menu in this case, press F8 after your computer completes its Power-On Self Test (usually indicated by a single beep) but before the Windows XP logo is displayed.
This message remains on the screen while the progress bar that tracks the loading of startup devices is displayed. If you press F8, you get to the Advanced Options menu, which looks like this:
Windows Advanced Options Menu Please select ...