Did you make any other changes besides tweaking the wireless router settings? How do you log-in to Windows? It sounds like your local user profile either got deleted accidently or is corrupted.
After tweaking my wireless router's settings and rebooting my computer, suddenly all of my computer's settings were reset. It is almost like it returned to factory defaults.
Upon reboot, Windows asked me if I wanted to register Windows 2000, as if it was the first time the computer had been started up. All of my favorites are gone, and all of my prefrences and settings in my programs have been reset. Also, my desktop wallpaper was set to default and only half of my desktop icons were there.
Thanks for any help