vivianalozano wrote:
I assume that a neighbour has an iphone that tries to sync to my itunes repeteadly making the window pop up every 5 minutes...
That really is not likely since the device would have to have at one time been physically connected and synced to your computer, AND Wi-Fi sync enabled while connected to your library, AND they'd have to be on your Wi-Fi network. Unless you have someone who did all this and lives within Wi-Fi range, and knows your network password, that's not what's happening.
Do you have any auxillary software add-ons to iTunes (e.g. Last.fm scrobbler)? Sometimes those get in the way of shutting iTunes down and it will re-open unless you shut the other software down first.