Squid inactive but pid file exist

[Antonello PAPA]

Plese help!
I'm usig FC4 and Squid 2.5STABLE9. I can't start squid. The squid.out say: 
"no running Copy".
If I do "ps aux | grep squid" I don't find any squid pid.
The GUI  say:  "squid inactive but pid file exist"
If I remove the pid file the GUI sai: "squid inactive but subsys locked"
Them if I restart squid from the GUI I get only one pid file and I think 
there should be two.
It appens when I was tring a configuration with some errors usig ntlm_auth.
It appens again and I don't know what to do. The first time I reinstalled 
all linux box.
thanks
Antonello