Index: devpcp/src/pmdas/windows/pmda.c
===================================================================
--- devpcp.orig/src/pmdas/windows/pmda.c	2007-04-03 14:43:18.982438000 +1000
+++ devpcp/src/pmdas/windows/pmda.c	2007-04-03 14:46:12.881306000 +1000
@@ -743,7 +743,7 @@ fetch_callback(pmdaMetric *mdesc, unsign
 	if (count != 2)	/* we need both "dummy" metric values below */
 	    return 0;
 
-	used_space = free_space * (1.0 - free_percent);
+	used_space = (free_space / free_percent) - free_space;
 	used = 1024 * (unsigned long long)used_space;	/* MB to KB */
 	avail = 1024 * (unsigned long long)free_space;	/* MB to KB */
 	capacity = used + avail;