Now it's time to REMOVE it. Right-click Computer -> Click Manage -> Select Disk Management. Vista and 7 use a separate partition for the boot record. DO NOT touch this partition. Find the partition Vista is on, right-click it, and click Delete Volume.[QUOTE]
that's grey in my case. what shoudl I do?
the partition with vista (the first OS I installed) says: system, active, primary partition
the partition with 7 says: boot, page file, crash dump, primary partition