In some cases, the operating system locks the interrupts exclusively, thereby preventing you from listening to these interrupts.
Windows 2000 does this for the mouse and keyboard interrupts.

In versions 11.1.0 and below of WinDriver, you can refer to WinDriver’s VB interrupt sample program (found in theWinDriver\vb\samples\interrupt directory and available also from Windows’ start-up menu) for a list of the common IRQs (floppy disk, mouse and keyboard) and their availability on different operating systems.
As indicated in this list, the mouse and keyboard interrupts cannot be used on Windows 2000.
You can also use this sample to listen to ISA interrupts, which are not exclusively locked by the OS.