diff --git a/MemoryModule.c b/MemoryModule.c
index 201b651..7e94232 100644
--- a/MemoryModule.c
+++ b/MemoryModule.c
@@ -33,6 +33,11 @@
 #include <stdio.h>
 #endif
 
+#ifndef IMAGE_SIZEOF_BASE_RELOCATION
+// Vista SDKs no longer define IMAGE_SIZEOF_BASE_RELOCATION!?
+#define IMAGE_SIZEOF_BASE_RELOCATION (sizeof(IMAGE_BASE_RELOCATION))
+#endif
+
 #include "MemoryModule.h"
 
 typedef struct {