Which vista services can I safely disable?

I have had “major privacy issues” on my vista system for over 1 yr. Knew someone was remotely logging into my machine, moving files, changing desktop,disabling security programs & reading mail, etc. Had my system reloaded twice in 12 months. Did not change a thing! Finally figured out that this is NOT a virus. Its someone who is logging in remotely and running right along w/me. I need to know what remote services I can disable, desktop, terminal whatever and secure system. I have LAN. I am a home user. I do not need to give anyone the ability to connect to my system.