Perhaps something like one of these?:
http://www.industrologic.com/uwdtpcdesc.htm
http://www.industrologic.com/uwdtdesc.htm

I beg your forgiveness if you think it is a commercial plug
for our products, but at least it is on topic.

(I wrote an article in Nuts&Volts a couple of years ago about
watchdog timers for microcontrollers, so at least I'm
contributing.)

I have found that devices like these are getting popular due
to Windows crashes, etc.