Partition Magic used to be truly excellent - one of the most-used apps in my kit. It went downhill some years ago, and I switched to Easeus which isn't as good as PM once was, but does a job.
Sometimes, when things are seriously hosed and Easeus doesn't fix it, I dig out a Linux-on-a-CD and use QTParted or GParted to fix things. They say they don't really do NTFS but if you don't tell 'em...