Dr watsons postmortem debugger why does it come up on my pc since installing zonealarm anti virus so

Dr Watson's debugger comes with Windows itself but it probably did not show up until you installed some software which enabled the debug key.

Anyway if you do not want/like Dr. Watson's debugger, go to

HKEY_LOCAL_MACHINE\Software\Microsoft\... NT\CurrentVersion\AeDebug key in the registry and

1) set "Auto" to 0 (ZERO)

2) Empty the value of "Debugger" string

3) Restart your computer