Quote Originally Posted by WinuxUser View Post
This is maybe because you didn't boot into Live mode, which is essential for Gparted to Delete whatever partitions your current installations have...

When you boot from your machine, the partitions gets mounted.... and there is no way you can delete them when they are mounted.. so the idea of booting into live mode is suggested so that they dont get mounted and you can delete them without any hesitations... Good Luck with gparted... hope this helps..
I actually tried it both ways with the same results.