You know that UAC prompt you get when running setup.exe for an IM client? Ever wondered why there's an UAC prompt in the first place? Because Windows assumes that setup.exe needs admin privileges (unless .exe explicitly states that it doesn't). This piece of engineering doesn't even have a concept of ~/bin. In fact, there is/was an official W7 guideline that said that all programs must go into %ProgramFiles%, which is a system directory. Now, what sort of a imbecile decided that it's a good idea to let an underprivileged account install into a system directory - UAC or not - is beyond me. So, please, don't mix Windows in. While Linux distros have their dark moments, Windows is just one big service pack now.