I'm a Mac guy, but I also use two PCs running WinXP Pro.
They both just recently started popping up windows that say:
"the web page you requested is not available offline. To view this page click connect."
I wasn't requesting any page, nor was I even online. Somehow my computer is doing it automatically.
Perhaps it's related to LimeWire, which I've since removed from my computer.
Any ideas?