diff --git a/Foundation/include/Poco/Activity.h b/Foundation/include/Poco/Activity.h
index 66c80d9ae..29c4d4c32 100644
--- a/Foundation/include/Poco/Activity.h
+++ b/Foundation/include/Poco/Activity.h
@@ -121,6 +121,11 @@ public:
 	void start()
 		/// Starts the activity by acquiring a
 		/// thread for it from the default thread pool.
+	{
+		start(ThreadPool::defaultPool());
+	}
+
+	void start(ThreadPool& pool)
 	{
 		FastMutex::ScopedLock lock(_mutex);
 		
@@ -131,7 +136,7 @@ public:
 			_running = true;
 			try
 			{
-				ThreadPool::defaultPool().start(*this);
+				pool.start(*this);
 			}
 			catch (...)
 			{
diff --git a/Foundation/include/Poco/Process.h b/Foundation/include/Poco/Process.h
index ead8a619e..2a82130fa 100644
--- a/Foundation/include/Poco/Process.h
+++ b/Foundation/include/Poco/Process.h
@@ -237,7 +237,7 @@ public:
 		/// Waits for the process specified by handle to terminate
 		/// and returns the exit code of the process.
 		
-	static void kill(const ProcessHandle& handle);
+	static void kill(ProcessHandle& handle);
 		/// Kills the process specified by handle.
 		///
 		/// This is preferable on Windows where process IDs
diff --git a/Foundation/include/Poco/Process_UNIX.h b/Foundation/include/Poco/Process_UNIX.h
index e976773b8..ecfa74f55 100644
--- a/Foundation/include/Poco/Process_UNIX.h
+++ b/Foundation/include/Poco/Process_UNIX.h
@@ -84,7 +84,7 @@ public:
 		Pipe* outPipe, 
 		Pipe* errPipe,
 		const EnvImpl& env);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 
diff --git a/Foundation/include/Poco/Process_VMS.h b/Foundation/include/Poco/Process_VMS.h
index 70ed3583d..668d67d56 100644
--- a/Foundation/include/Poco/Process_VMS.h
+++ b/Foundation/include/Poco/Process_VMS.h
@@ -85,7 +85,7 @@ public:
 		Pipe* errPipe,
 		const EnvImpl& env);
 	static int waitImpl(PIDImpl pid);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 };
diff --git a/Foundation/include/Poco/Process_VX.h b/Foundation/include/Poco/Process_VX.h
index 9bc7ba248..767d0535a 100644
--- a/Foundation/include/Poco/Process_VX.h
+++ b/Foundation/include/Poco/Process_VX.h
@@ -86,7 +86,7 @@ public:
 		Pipe* outPipe, 
 		Pipe* errPipe,
 		const EnvImpl& env);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 };
diff --git a/Foundation/include/Poco/Process_WIN32.h b/Foundation/include/Poco/Process_WIN32.h
index 3e9bc4037..fdc7ab3c8 100644
--- a/Foundation/include/Poco/Process_WIN32.h
+++ b/Foundation/include/Poco/Process_WIN32.h
@@ -62,7 +62,8 @@ public:
 	UInt32 id() const;
 	HANDLE process() const;
 	int wait() const;
-	
+	void closeHandle();
+
 private:
 	HANDLE _hProcess;
 	UInt32 _pid;
@@ -89,7 +90,7 @@ public:
 		Pipe* outPipe, 
 		Pipe* errPipe,
 		const EnvImpl& env);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 	static std::string terminationEventName(PIDImpl pid);
diff --git a/Foundation/include/Poco/Process_WIN32U.h b/Foundation/include/Poco/Process_WIN32U.h
index 5ba4164ea..0396fa632 100644
--- a/Foundation/include/Poco/Process_WIN32U.h
+++ b/Foundation/include/Poco/Process_WIN32U.h
@@ -62,6 +62,7 @@ public:
 	UInt32 id() const;
 	HANDLE process() const;
 	int wait() const;
+	void closeHandle();
 
 private:
 	HANDLE _hProcess;
@@ -89,7 +90,7 @@ public:
 		Pipe* outPipe, 
 		Pipe* errPipe,
 		const EnvImpl& env);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 	static std::string terminationEventName(PIDImpl pid);
diff --git a/Foundation/include/Poco/Process_WINCE.h b/Foundation/include/Poco/Process_WINCE.h
index a25aca804..868cc4d85 100644
--- a/Foundation/include/Poco/Process_WINCE.h
+++ b/Foundation/include/Poco/Process_WINCE.h
@@ -62,7 +62,8 @@ public:
 	UInt32 id() const;
 	HANDLE process() const;
 	int wait() const;
-	
+	void closeHandle();
+
 private:
 	HANDLE _hProcess;
 	UInt32 _pid;
@@ -89,7 +90,7 @@ public:
 		Pipe* outPipe, 
 		Pipe* errPipe,
 		const EnvImpl& env);
-	static void killImpl(const ProcessHandleImpl& handle);
+	static void killImpl(ProcessHandleImpl& handle);
 	static void killImpl(PIDImpl pid);
 	static void requestTerminationImpl(PIDImpl pid);
 	static std::string terminationEventName(PIDImpl pid);
diff --git a/Foundation/src/Process.cpp b/Foundation/src/Process.cpp
index eb90f6748..378841661 100644
--- a/Foundation/src/Process.cpp
+++ b/Foundation/src/Process.cpp
@@ -200,7 +200,7 @@ int Process::wait(const ProcessHandle& handle)
 }
 
 
-void Process::kill(const ProcessHandle& handle)
+void Process::kill(ProcessHandle& handle)
 {
 	killImpl(*handle._pImpl);
 }
diff --git a/Foundation/src/Process_UNIX.cpp b/Foundation/src/Process_UNIX.cpp
index d64885743..ff2adec0a 100644
--- a/Foundation/src/Process_UNIX.cpp
+++ b/Foundation/src/Process_UNIX.cpp
@@ -218,7 +218,7 @@ ProcessHandleImpl* ProcessImpl::launchByForkExecImpl(const std::string& command,
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
 	killImpl(handle.id());
 }
diff --git a/Foundation/src/Process_VMS.cpp b/Foundation/src/Process_VMS.cpp
index 7508a286d..0fcc3e759 100644
--- a/Foundation/src/Process_VMS.cpp
+++ b/Foundation/src/Process_VMS.cpp
@@ -137,7 +137,7 @@ ProcessHandleImpl* ProcessImpl::launchImpl(const std::string& command, const Arg
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
 	killImpl(handle.id());
 }
diff --git a/Foundation/src/Process_VX.cpp b/Foundation/src/Process_VX.cpp
index 1304267ea..caad13cf2 100644
--- a/Foundation/src/Process_VX.cpp
+++ b/Foundation/src/Process_VX.cpp
@@ -89,7 +89,7 @@ ProcessHandleImpl* ProcessImpl::launchImpl(const std::string& command, const Arg
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
 	throw Poco::NotImplementedException("Process::kill()");
 }
diff --git a/Foundation/src/Process_WIN32.cpp b/Foundation/src/Process_WIN32.cpp
index a338f3a88..96e936fe6 100644
--- a/Foundation/src/Process_WIN32.cpp
+++ b/Foundation/src/Process_WIN32.cpp
@@ -56,9 +56,17 @@ ProcessHandleImpl::ProcessHandleImpl(HANDLE hProcess, UInt32 pid):
 
 ProcessHandleImpl::~ProcessHandleImpl()
 {
-	CloseHandle(_hProcess);
+	closeHandle();
 }
 
+void ProcessHandleImpl::closeHandle()
+{
+	if (_hProcess)
+	{
+		CloseHandle(_hProcess);
+		_hProcess = NULL;
+	}
+}
 
 UInt32 ProcessHandleImpl::id() const
 {
@@ -228,17 +236,19 @@ ProcessHandleImpl* ProcessImpl::launchImpl(const std::string& command, const Arg
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
-	if (TerminateProcess(handle.process(), 0) == 0)
+	if (handle.process()) 
 	{
-		CloseHandle(handle.process());
-		throw SystemException("cannot kill process");
+		if (TerminateProcess(handle.process(), 0) == 0)
+		{
+			handle.closeHandle();
+			throw SystemException("cannot kill process");
+		}
+		handle.closeHandle();
 	}
-	CloseHandle(handle.process());
 }
 
-
 void ProcessImpl::killImpl(PIDImpl pid)
 {
 	HANDLE hProc = OpenProcess(PROCESS_TERMINATE, FALSE, pid);
diff --git a/Foundation/src/Process_WIN32U.cpp b/Foundation/src/Process_WIN32U.cpp
index 3fd54504b..869c995fc 100644
--- a/Foundation/src/Process_WIN32U.cpp
+++ b/Foundation/src/Process_WIN32U.cpp
@@ -57,9 +57,17 @@ ProcessHandleImpl::ProcessHandleImpl(HANDLE hProcess, UInt32 pid):
 
 ProcessHandleImpl::~ProcessHandleImpl()
 {
-	CloseHandle(_hProcess);
+	closeHandle();
 }
 
+void ProcessHandleImpl::closeHandle()
+{
+	if (_hProcess)
+	{
+		CloseHandle(_hProcess);
+		_hProcess = NULL;
+	}
+}
 
 UInt32 ProcessHandleImpl::id() const
 {
@@ -234,17 +242,19 @@ ProcessHandleImpl* ProcessImpl::launchImpl(const std::string& command, const Arg
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
-	if (TerminateProcess(handle.process(), 0) == 0)
+	if (handle.process())
 	{
-		CloseHandle(handle.process());
-		throw SystemException("cannot kill process");
+		if (TerminateProcess(handle.process(), 0) == 0)
+		{
+			handle.closeHandle();
+			throw SystemException("cannot kill process");
+		}
+		handle.closeHandle();
 	}
-	CloseHandle(handle.process());
 }
 
-
 void ProcessImpl::killImpl(PIDImpl pid)
 {
 	HANDLE hProc = OpenProcess(PROCESS_TERMINATE, FALSE, pid);
diff --git a/Foundation/src/Process_WINCE.cpp b/Foundation/src/Process_WINCE.cpp
index 366fc6ed1..bf7d91cb8 100644
--- a/Foundation/src/Process_WINCE.cpp
+++ b/Foundation/src/Process_WINCE.cpp
@@ -57,9 +57,17 @@ ProcessHandleImpl::ProcessHandleImpl(HANDLE hProcess, UInt32 pid):
 
 ProcessHandleImpl::~ProcessHandleImpl()
 {
-	CloseHandle(_hProcess);
+	closeHandle();
 }
 
+void ProcessHandleImpl::closeHandle()
+{
+	if (_hProcess)
+	{
+		CloseHandle(_hProcess);
+		_hProcess = NULL;
+	}
+}
 
 UInt32 ProcessHandleImpl::id() const
 {
@@ -158,14 +166,17 @@ ProcessHandleImpl* ProcessImpl::launchImpl(const std::string& command, const Arg
 }
 
 
-void ProcessImpl::killImpl(const ProcessHandleImpl& handle)
+void ProcessImpl::killImpl(ProcessHandleImpl& handle)
 {
-	if (TerminateProcess(handle.process(), 0) == 0)
+	if (handle.process()) 
 	{
-		CloseHandle(handle.process());
-		throw SystemException("cannot kill process");
+		if (TerminateProcess(handle.process(), 0) == 0)
+		{
+			handle.closeHandle();
+			throw SystemException("cannot kill process");
+		}
+		handle.closeHandle();
 	}
-	CloseHandle(handle.process());
 }