WIndows 7 won't let me format a hard drive

I have a 750Gb drive that I would like to reformat so I can use it for backups. When I try to format the drive I am told windows can't format it.

The drive was previously used as a C drive and held an intstalation of Vista. On the drives and Proram and Windows folders. When I tried to delete them I was told I needed permission from trusted installer. I found a "solution" to this on a microsoft site which effectively said to set the owner to the administrator group. I have done this. Now when I try and delete them I am told I need permission from the administrator. I have logged on as the administrator.

Formatting is also still forbidden.

The files I want rid of take up 50Gb of space.

HELP

Hello ianoh and welcome to Seven Forums.

This Microsoft Answers forum thread might help. Particularly about using the diskpart utility to format the drive. As I understand it (and I could be wrong on this) since the hard drive was previously used as a C: drive and contained Vista, it might still be recognized by Windows 7 as a boot drive and that's why you can't format it.

Cannot format drive - Microsoft Answers

Another possibility is to get gparted iso, burn it to a CD (or a flash drive following the instructions here). Boot from the CD or flash drive and then you can format/delete/move/resize/etc partitions from there.

Thanks for this. I would be happy to leave the drive as it is if I could only delete all the files. I can't believe 15Gb of files are essential.

Ian