How can I disable WinVNC on my computer?

One of the guys that works in the IT dept. is completely infatuated with me. He keeps using the VNC software as spyware to monitor where I go on-line. Because of this he knows what I do, what my schedule is & anything else there is to know from my online surfing. This is completely creeping me out. He shows up at the same networking functions, seminars & even if I have lunch/dinner with a client he knows where I am going & when I am going there. It's disturbing & scary. He seems to get off on it. I tried to talk to my superiors about it but he just denys it. It's my word against his & he's been there longer. I know he's using the VNC software because that's what our company uses. Is there any way I can block it? Please help!