Mountain Lion Crashed First Time

Today my Mac suddenly crashed. This is the first time I saw a crash after I updated my Mac to ML. My Mac has been running for several days. This afternoon, I logged in to my Mac when I got home after work. Within seconds, My screen suddenly became a while screen, just like a new start. Soon there was a message in the center of the screen about the crash. I tried to read the message, but I was not able to read them. The restart cleared the screen.

After the restart, I got a message about the reboot.

I clicked on Report button, a detail information was displayed. I am not sure if there was commend available before Mountain Lion. I clicked on Comments and I could write something there to tell what was happened.

Before ML, I had several times of blue screen. The blue screen happened like a curtain rolling down from top, and the whole screen became disabled. I had no time to respond or control my UI, and no time to save anything. The blue screen displayed a message about unexpected system panic. I was forced to turn off power. Not sure my sudden crash is the same case of blue screen.