diff --git a/reactos/include/idl/svcctl.idl b/reactos/include/idl/svcctl.idl
index 105d2f019c8..bfdaa0f66ef 100644
--- a/reactos/include/idl/svcctl.idl
+++ b/reactos/include/idl/svcctl.idl
@@ -136,6 +136,13 @@ cpp_quote("#endif")
                                    [out, size_is(*lpcchBuffer), unique] LPWSTR lpDisplayName,
                                    [in, out, ref] LPDWORD lpcchBuffer);
 
+  /* Function 21 */
+  DWORD ScmrGetServiceKeyNameW([in] handle_t BindingHandle,
+                               [in] SC_HANDLE hSCManager,
+                               [in, string, ref] LPCWSTR lpDisplayName,
+                               [out, size_is(*lpcchBuffer), unique] LPWSTR lpServiceName,
+                               [in, out, ref] LPDWORD lpcchBuffer);
+
 
   /* Function 27 */
   DWORD ScmrOpenSCManagerA([in] handle_t BindingHandle,
diff --git a/reactos/lib/advapi32/service/scm.c b/reactos/lib/advapi32/service/scm.c
index 5de26b7ba97..f429ef67daf 100644
--- a/reactos/lib/advapi32/service/scm.c
+++ b/reactos/lib/advapi32/service/scm.c
@@ -618,7 +618,7 @@ GetServiceKeyNameA(
 /**********************************************************************
  *  GetServiceKeyNameW
  *
- * @unimplemented
+ * @implemented
  */
 BOOL STDCALL
 GetServiceKeyNameW(SC_HANDLE hSCManager,
@@ -626,7 +626,6 @@ GetServiceKeyNameW(SC_HANDLE hSCManager,
                    LPWSTR lpServiceName,
                    LPDWORD lpcchBuffer)
 {
-#if 0
     DWORD dwError;
 
     DPRINT("GetServiceKeyNameW() called\n");
@@ -646,10 +645,6 @@ GetServiceKeyNameW(SC_HANDLE hSCManager,
     }
 
     return TRUE;
-#endif
-    DPRINT1("GetServiceKeyNameW is unimplemented\n");
-    SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
-    return FALSE;
 }
 
 
diff --git a/reactos/subsys/system/services/rpcserver.c b/reactos/subsys/system/services/rpcserver.c
index 27b04060163..d7e0f79ef58 100644
--- a/reactos/subsys/system/services/rpcserver.c
+++ b/reactos/subsys/system/services/rpcserver.c
@@ -348,7 +348,15 @@ ScmrDeleteService(handle_t BindingHandle,
 
     /* FIXME: Acquire service database lock exclusively */
 
+    if (lpService->bDeleted)
+    {
+        DPRINT1("The service has already been marked for delete!\n");
+        return ERROR_SERVICE_MARKED_FOR_DELETE;
+    }
+
     /* Mark service for delete */
+    lpService->bDeleted = TRUE;
+
     dwError = ScmMarkServiceForDelete(lpService);
 
     /* FIXME: Release service database lock */
@@ -533,8 +541,19 @@ ScmrChangeServiceConfigW(handle_t BiningHandle,
         return ERROR_INVALID_HANDLE;
     }
 
+    /* FIXME: Lock database exclusively */
+
+    if (lpService->bDeleted)
+    {
+        /* FIXME: Unlock database */
+        DPRINT1("The service has already been marked for delete!\n");
+        return ERROR_SERVICE_MARKED_FOR_DELETE;
+    }
+
     /* FIXME: ... */
 
+    /* FIXME: Unlock database */
+
     DPRINT1("ScmrChangeServiceConfigW() done (Error %lu)\n", dwError);
 
     return dwError;
@@ -1007,6 +1026,56 @@ ScmrGetServiceDisplayNameW(handle_t BindingHandle,
 }
 
 
+/* Function 21 */
+unsigned long
+ScmrGetServiceKeyNameW(handle_t BindingHandle,
+                       unsigned int hSCManager,
+                       wchar_t *lpDisplayName,
+                       wchar_t *lpServiceName, /* [out, unique] */
+                       unsigned long *lpcchBuffer)
+{
+//    PMANAGER_HANDLE hManager;
+    PSERVICE lpService;
+    DWORD dwLength;
+    DWORD dwError;
+
+    DPRINT1("ScmrGetServiceKeyNameW() called\n");
+    DPRINT1("hSCManager = %x\n", hSCManager);
+    DPRINT1("lpDisplayName: %S\n", lpDisplayName);
+    DPRINT1("lpServiceName: %p\n", lpServiceName);
+    DPRINT1("*lpcchBuffer: %lu\n", *lpcchBuffer);
+
+//    hManager = (PMANAGER_HANDLE)hSCManager;
+//    if (hManager->Handle.Tag != MANAGER_TAG)
+//    {
+//        DPRINT1("Invalid manager handle!\n");
+//        return ERROR_INVALID_HANDLE;
+//    }
+
+    /* Get service database entry */
+    lpService = ScmGetServiceEntryByDisplayName(lpDisplayName);
+    if (lpService == NULL)
+    {
+        DPRINT1("Could not find a service!\n");
+        return ERROR_SERVICE_DOES_NOT_EXIST;
+    }
+
+    dwLength = wcslen(lpService->lpServiceName);
+
+    if (lpServiceName != NULL &&
+        *lpcchBuffer > dwLength)
+    {
+        wcscpy(lpServiceName, lpService->lpServiceName);
+    }
+
+    dwError = (*lpcchBuffer > dwLength) ? ERROR_SUCCESS : ERROR_INSUFFICIENT_BUFFER;
+
+    *lpcchBuffer = dwLength;
+
+    return dwError;
+}
+
+
 /* Function 27 */
 unsigned long
 ScmrOpenSCManagerA(handle_t BindingHandle,
diff --git a/reactos/subsys/system/services/services.h b/reactos/subsys/system/services/services.h
index cb38b3f36bb..2e65d890274 100644
--- a/reactos/subsys/system/services/services.h
+++ b/reactos/subsys/system/services/services.h
@@ -15,6 +15,7 @@ typedef struct _SERVICE
     LPWSTR lpServiceName;
     LPWSTR lpDisplayName;
     UNICODE_STRING ServiceGroup;
+    BOOL bDeleted;
 
     SERVICE_STATUS Status;
     DWORD dwStartType;