It seems to be gone now, but did anyone else catch the the link to sign up for an account at the bottom of the main google search page today? Either they're just about ready to finally launch for real or, since it's gone now, they were just trying to get more testers since they've probably exhausted invites as a way of doing this.
Are you sure it's just not minimized? Move the pointer to the bottom of the screen, and see if you get the arrow cursor. Or, maybe you're monitor settings are off. Check your video card drivers, and try the hardware settings on your monitor.