In the past I have been able to connect via screensharing (finder/go to server vnc://IP) to my i-Mac at work from my mac-mini just fine. However, when I tried today, I wasn't able to see the login prompt. I gave a co-worker my IP and he was able to see it. I was able to ssh into the box and perform a reboot. The same thing happened. I was able to see the default login background (galaxy thing), but no login prompt. Co-worker verified he saw login prompt.
I can't pinpoint when it happened, but I thought it was that I was running leopard at work and lion at home. My coworker was running mountain lion to connect when he saw the prompt so I upgraded to mountain lion at home in the hopes that it would fix it, but it didn't.
I tried rebooting home, remote, using chicken of the vnc. I don't have mobile me so it's not the signed in issue. I'm at a loss.
UPDATE: I just noticed something odd. What's weird is that the screen on the right which should have the login prompt, had a grey bar at the top of the screen. The height would seem to match the OSX taskbar. odd.