For the past few weeks I've been having issues with explorer.exe locking up every so often. The first sign of trouble is when the icon for the strength of the signal in the notification area stays at 5 empty bars with an unmoving blue ring imposed over it. Clicking on the icon causes explorer.exe to freeze; I'm unable to right click on the taskbar to start the task manager, and when I open it via the option given from Ctrl-Alt-Del, the task manager goes Non Responsive when I tell it to kill a program. Occasionally, by clicking the taskbar repeatedly, I am given the message box that explorer.exe is unresponsive and am given the choice to wait, restart it, or shut it down. Restarting it produces no positive result; explorer.exe behaves well until I click the icon again, which does not change as a result of the restart.
Additionally, my browser begins acting up. New tabs open up to blank screens that never load and entering in URLs in the address bar produces no result. Note that this behavior happen before I click icon and explorer.exe becomes unresponsive; in fact, it's usually this behavior that causes me to notice that the icon is behaving erroneously.
I've noticed there's a correlation between when this happens and when I change wireless signals. I live between two houses and visit friends' houses, and this happens fairly consistently when I bring my computer out of hibernation at a new primary signal. The problem is resolved once I restart the computer (though I have to do so by holding down the power button until it shuts down because the start menu options for restart, shut down, ect., are also locked up). I haven't paid quite enough attention to notice if this happens at other times, but it's a possible cause.