After you attempt to start your computer in Safe mode by pressing the F8 key at the Microsoft Windows XP boot menu screen, and then selecting one of the Safe mode options, your computer keyboard or mouse may not respond when you try to use them.
The behavior can occur if you are using a Universal Serial Bus (USB) keyboard or mouse and your computer basic input/output system (BIOS) does not support USB devices. Windows XP does not support the use of a USB keyboard or mouse in Safe mode unless the computer BIOS supports these devices.
To work around this behavior, use a standard keyboard or mouse instead of aUSB keyboard or mouse.
This behavior is by design.
In the case of USB input devices, in order for them to function in Safe mode, the system must have a BIOS with USB support for input devices and USB legacy mode must be enabled.
NOTE: All other USB devices are not loaded in Safe mode, unless the manufacturer requires it and provides BIOS support for that USB device in addition to input devices.