What does this computer problem mean?

I was on my computer adding photos and then a thing popped up that said catostrophic failure. The only option was okay, so I clicked that. Then it began to download the instruction manual for the computer for troubleshooting. It automatically scrolled to the page on troubleshooting Internet problems ( I wasn't even on internet) and then it said it was doing an emergency restart. It never cane back on and I can't get it too. I'm asking this on my iPod.