When TweetDeck goes unresponsive, it takes Windows 7 10 seconds to decide to actually close it.
Is there a reg key I can set that makes it instakill itself?
Not quite what you're asking, but if you kill it from the process tab of task manager (ctrl-shift-escape) as opposed to the application tab or from explorer then it will be killed instantly. The other two post quit messages to its Windows message queue to give it a chance - the ten seconds - to react itself.
You can disable the "Windows is checking for a solution to the problem... " message and skip right to the close program dialog. From the Start menu, search for Action Center and open that. From there choose Change Action Center settings. At the bottom is Problem Reporting settings. Click that, and set it to Never check.