My compuer logs on the network twice? Do I have a virus?

Strange… I turn on the computer. It logs itself into my home network. Skpe, IM and mail all start up fine and start receiving messages.

Then about a minute later… my Network log on box pops up. If I see it, I hit cancel.
If I don’t see it in time, it just logs in and disappears. What’s going on? This is strange.

OS Windows 7 pro Chinese with English interface.