i think you could have to repartion and reformat it to get rid of that presky disk management. If you are using Windows XP, then when setup is ready to proceed, delete all partions and leave the RAW partion. force it to format in NTFS (not quick) and install along way! Same goes to windows 2k.
Windows 98, use latest FDISK from Microsoft Windows Knowledge Base KB263044. Delete and repartion the disk and format the disk before install windows 9x.