Cygwin stops after Norton antivirus install

Cygwin was working fine before I install Norton on my laptop开发者_开发百科. Cygwin window not even shows the command prompt. How to fix this? I am using Win7

Thanks in advance.

Norton is high up on Cygwin's Big List Of Dodgy Applications at http://cygwin.com/faq/faq.using.html#faq.using.bloda. These applications often install hooks into other processes, yet they don't do so entirely transparently, thereby breaking crucial Cygwin functionality, in particular its fork() implementation.

So far MS's Security Essentials appears to be Cygwin-compatible, but these things change ...