This kind of thing can really be a pain to track down; you have to start investigating until you find the culprit. Sometimes the problem suddenly stops and you never do find the reason! Usually it is something that is scheduled to update; try to remember when the first occurrence was and did you install a program, change a configuration in the system properties? Time this between happenings - does it happen at regular intervals or is it random times? Check all your utilities that have to regularly update, such as your antivirus, firewall, flash player, Java, etc. and also look for other programs that have "scheduled themselves" without your knowledge to access the internet and update. The fact that you are not crashing or rebooting means that it is not anything that is foreign to the system. However, I suggest that you immediately run a full, in-depth scan of your system with your anitvirus. I also suggest download and run Malwareytes (you can get it from File Hippo)just for further safety. Sometimes backdoor trojans with keyloggers will "dial home" with information. Let us know how it goes. Good hunting!
[EDIT]: I just remembered the (free) firewall, Comodo. Comodo firewall is really good, and it will alert you to any non-Windows system that attempts to dial out. It is a bit of a pain, because it also installs the Comodo antivirus and "Geek Buddy" utilities, but you can uninstall them as separate modules. You don't want multiple antivirus programs running at the same time.
Edited by ranchhand3, 24 August 2012 - 02:04 PM.