diff --git a/src/os/win32/peb.c b/src/os/win32/peb.c
index 153effe9..4fdbfcb8 100644
--- a/src/os/win32/peb.c
+++ b/src/os/win32/peb.c
@@ -99,6 +99,9 @@ int sigar_proc_exe_peb_get(sigar_t *sigar, HANDLE proc,
     RTL_USER_PROCESS_PARAMETERS rtl;
     DWORD size;
 
+    procexe->name[0] = '\0';
+    procexe->cwd[0] = '\0';
+
     if ((status = sigar_rtl_get(sigar, proc, &rtl)) != SIGAR_OK) {
         return status;
     }
@@ -111,9 +114,6 @@ int sigar_proc_exe_peb_get(sigar_t *sigar, HANDLE proc,
     {
         SIGAR_W2A(buf, procexe->name, sizeof(procexe->name));
     }
-    else {
-        procexe->name[0] = '\0';
-    }
 
     size = rtl_bufsize(buf, rtl.CurrentDirectoryName);
     memset(buf, '\0', sizeof(buf));
@@ -123,9 +123,6 @@ int sigar_proc_exe_peb_get(sigar_t *sigar, HANDLE proc,
     {
         SIGAR_W2A(buf, procexe->cwd, sizeof(procexe->cwd));
     }
-    else {
-        procexe->cwd[0] = '\0';
-    }
 
     return SIGAR_OK;
 }
@@ -171,15 +168,16 @@ int sigar_proc_args_peb_get(sigar_t *sigar, HANDLE proc,
     }
 
     size = rtl_bufsize(buf, rtl.CommandLine);
+    if (size <= 0) {
+        return ERROR_DATATYPE_MISMATCH; /* fallback to wmi */
+    }
     memset(buf, '\0', sizeof(buf));
-            
-    if ((size > 0) &&
-        ReadProcessMemory(proc, rtl.CommandLine.Buffer, buf, size, NULL))
-    {
+
+    if (ReadProcessMemory(proc, rtl.CommandLine.Buffer, buf, size, NULL)) {
         return sigar_parse_proc_args(sigar, buf, procargs);
     }
     else {
-        return SIGAR_OK;
+        return GetLastError();
     }
 }
 
diff --git a/src/os/win32/win32_sigar.c b/src/os/win32/win32_sigar.c
index 9d61ba0a..ccbc8c37 100644
--- a/src/os/win32/win32_sigar.c
+++ b/src/os/win32/win32_sigar.c
@@ -1435,19 +1435,21 @@ static int sigar_remote_proc_args_get(sigar_t *sigar, sigar_pid_t pid,
     char cmdline[SIGAR_CMDLINE_MAX], *ptr = cmdline, *arg;
     HANDLE proc = open_process(pid);
 
-    if (!proc) {
-        return GetLastError();
+    if (proc) {
+        status = sigar_proc_args_peb_get(sigar, proc, procargs);
+
+        CloseHandle(proc);
+
+        if (status == SIGAR_OK) {
+            return status;
+        }
     }
 
-    status = sigar_proc_args_peb_get(sigar, proc, procargs);
-
-    CloseHandle(proc);
-
-    if (status == ERROR_DATATYPE_MISMATCH) {
-        /* we are 32-bit, pid process is 64-bit */
-        status = sigar_proc_args_wmi_get(sigar, pid, procargs);
+    /* likely we are 32-bit, pid process is 64-bit */
+    status = sigar_proc_args_wmi_get(sigar, pid, procargs);
+    if (status == ERROR_NOT_FOUND) {
+        status = SIGAR_NO_SUCH_PROCESS;
     }
-
     return status;
 }
 
@@ -1608,10 +1610,13 @@ SIGAR_DECLARE(int) sigar_proc_exe_get(sigar_t *sigar, sigar_pid_t pid,
     }
 
     status = sigar_proc_exe_peb_get(sigar, proc, procexe);
-    if (status == ERROR_DATATYPE_MISMATCH) {
-        /* we are 32-bit, pid process is 64-bit */
-        procexe->cwd[0] = '\0'; /* XXX where else can we try? */
+    if (procexe->name[0] == '\0') {
+        /* likely we are 32-bit, pid process is 64-bit */
+        /* procexe->cwd[0] = XXX where else can we try? */
         status = sigar_proc_exe_wmi_get(sigar, pid, procexe);
+        if (status == ERROR_NOT_FOUND) {
+            status = SIGAR_NO_SUCH_PROCESS;
+        }
     }
 
     if (procexe->cwd[0] != '\0') {
diff --git a/src/os/win32/wmi.cpp b/src/os/win32/wmi.cpp
index a816bbd9..82229cab 100644
--- a/src/os/win32/wmi.cpp
+++ b/src/os/win32/wmi.cpp
@@ -42,15 +42,18 @@ class WMI {
     HRESULT GetProcStringProperty(DWORD pid, TCHAR *name, TCHAR *value, DWORD len);
     HRESULT GetProcExecutablePath(DWORD pid, TCHAR *value);
     HRESULT GetProcCommandLine(DWORD pid, TCHAR *value);
+    int GetLastError();
 
   private:
     IWbemServices *wbem;
+    HRESULT result;
     BSTR GetProcQuery(DWORD pid);
 };
 
 WMI::WMI()
 {
     wbem = NULL;
+    result = S_OK;
     CoInitializeEx(NULL, COINIT_MULTITHREADED);
 }
 
@@ -60,14 +63,31 @@ WMI::~WMI()
     CoUninitialize();
 }
 
+/* XXX must be a better way to map HRESULT */
+int WMI::GetLastError()
+{
+    switch (result) {
+      case S_OK:
+        return ERROR_SUCCESS;
+      case WBEM_E_NOT_FOUND:
+        return ERROR_NOT_FOUND;
+      case WBEM_E_ACCESS_DENIED:
+        return ERROR_ACCESS_DENIED;
+      case WBEM_E_NOT_SUPPORTED:
+        return SIGAR_ENOTIMPL;
+      default:
+        return ERROR_INVALID_FUNCTION;
+    }
+}
+
 HRESULT WMI::Open(LPCTSTR machine, LPCTSTR user, LPCTSTR pass)
 {
-    HRESULT result;
     IWbemLocator *locator;
     wchar_t path[MAX_PATH];
 
     if (wbem) {
-        return S_OK;
+        result = S_OK;
+        return result;
     }
 
     result =
@@ -116,6 +136,7 @@ void WMI::Close()
     if (wbem) {
         wbem->Release();
         wbem = NULL;
+        result = S_OK;
     }
 }
 
@@ -128,7 +149,6 @@ BSTR WMI::GetProcQuery(DWORD pid)
 
 HRESULT WMI::GetProcStringProperty(DWORD pid, TCHAR *name, TCHAR *value, DWORD len)
 {
-    HRESULT result;
     IWbemClassObject *obj;
     VARIANT var;
 
@@ -177,11 +197,11 @@ extern "C" int sigar_proc_args_wmi_get(sigar_t *sigar, sigar_pid_t pid,
     WMI *wmi = new WMI();
 
     if (FAILED(wmi->Open())) {
-        return GetLastError();
+        return wmi->GetLastError();
     }
 
     if (FAILED(wmi->GetProcCommandLine(pid, buf))) {
-        status = GetLastError();
+        status = wmi->GetLastError();
     }
     else {
         status = sigar_parse_proc_args(sigar, buf, procargs);
@@ -201,13 +221,13 @@ extern "C" int sigar_proc_exe_wmi_get(sigar_t *sigar, sigar_pid_t pid,
     WMI *wmi = new WMI();
 
     if (FAILED(wmi->Open())) {
-        return GetLastError();
+        return wmi->GetLastError();
     }
 
     procexe->name[0] = '\0';
 
     if (FAILED(wmi->GetProcExecutablePath(pid, buf))) {
-        status = GetLastError();
+        status = wmi->GetLastError();
     }
     else {
         status = SIGAR_OK;