My very first thought here was going "old school" and deleting the drive the old way! I know most computers now a days do not come stock standard with a diskette drive. But if yours does, and you've got an old MSDOS diskette laying around, say version 4.0 or higher, I would use that. Format the drive through MSDOS, when prompted to I would type in FORMAT C: and sit back and watch the old magic. Then with your Windows 7 installation disk, I would go about formatting the drive to NTFS and whoola your home!
I know the MSDOS thing here was an odd and silly recommendation, I just reverted to old school for a minute.....sorry.