Thunderbird (email program) crashes my computer sometimes.  I also have a Hauppauge TV adapter and program that I watch TV on my computer.  If I use it or Windows Media Center to watch TV and then run Thunderbird or vice versa my computer crashes.  Not every time but often enough that I'm certain they don't like each other.

To date I've been logging off and the logging back on, that seems to have stopped the problem.  But I wondered if there is another way to clear the memory of all the programs running in the background. 

Going to the Task Manager and searching for what I think are the culprits takes longer than logging off and on.