Under the Start menu, select All Programs, then Accessories, then Accessibility, and then On-Screen Keyboard. When you do this the Windows XP on-screen keyboard will appear on your screen.
AppleKeys
AppleKeys allows the use of Apple keyboards on a Windows machine. It properly emulates the F13 - F15 keys to “print screen, scroll lock, and pause/break” accordingly. AppleKeys 2 pentru Windows XP