Mark Partition As Active Greyed Out

I thought I'd find a use for a Sandisk 60GB stick by installing Windows 8 on it as I have a Win 8 DVD. Followed the process HERE and everything went OK until it got to marking the partition Active - that is greyed out. Disk Management shows just the one NTFS partition marked Healthy (Primary Partition) so there isn't another Active partition on the drive. Looks like I shall have to reformat the drive and try again unless anyone here has any suggestions. The USB stick was originally a backup disk with a Backup button on it and I suspect it has some hidden boot code preventing the Active flag from being set.

 

Partition Wizard boot disk came to the rescue and the stick is now booting.