Spiral Knights is "special" game.
Its the only game that can crash my computer to the point i have to do hard reset.
It never happens with any of my other games, starting from old games for win 95 that you could expect to run strange in new systems and in 64 bit and ending with newest games running on highest graphics settings like crysis 2, diablo 3 etc.
Did you read the sticky at the top of this forum?
You'll need to provide more information than that in order for anyone to help you. Go through the stickied thread at the top of this forum and try those troubleshooting options; if none of that helps post your computer specifications and more information about what SK is doing when it crashes.