events and backgroundworker thread

[Analizer1]

Hi ...
I have lets say 4 backgroundworke r thread running
they all connect to sqlserver2005 does some processing

where im having problems..its on critical errors
lets say the sqlserver is down..

so tons of errors are kicked off , where as i catch them
at different places in the code, try/catch blocks

what i want to do is stop the threads (not destroy)
and tell the service to stop

any advice on how to accomplish this.....
I did create a eventhandler but seems im still stuck in several stacks for
the threads when this event is fired

thanks