Background

I'm using a Windows XP tablet PC connected to my home network. I do broadcast the SSID, but otherwise the wireless network is locked down as tight as I can make it - WPA2 with a strong key, MAC filtering, etc. I've had this computer for about 4 years and the router for about 6 months. Before that, the previous router was set up in the same way, and I've never had any particular problems.

Problem

This morning - as I type this, as a matter of fact - Windows is reporting that none of my network connections are connected. Yet somehow my Internet connectivity still works! ipconfig reports a valid IP address, domain, etc., even though Windows apparently doesn't know about it. I tried repairing the connection and it had no effect - the repair eventually timed out.

I'm pretty sure that I could reboot the computer and/or the router, etc. and it would fix the problem. However, I'm more interested in knowing if any of you have ever seen anything like this, and what might have caused it? Since it works I'm not inclined to mess with it too much. My concern is that it's a precursor to bigger problems.