That seems odd since I've used GParted for resizing both XP and Vista primaries without anything go bad. Are you sure you didn't have a bad burn? Make sure the version you use is "platform independent" as well like the 0.3.3.0 version. Unfortunately that's the last of that line. Fortunately you can now resize NTFS partitions by a boot from the Vista install disk or in the updated Disk Management tool.