How do I fix this and install grub?
When I use gparted I see /dev/sdb has one partition and it is ext4 however when I tried to install grub I got
/usr/sbin/grub-setup: error: hd0 appears to contain a iso9660 filesystem which isn't known to reserve space for DOS-style boot. Installing GRUB there could result in FILESYSTEM DESTRUCTION if valuable data is overwritten by grub-setup (--skip-fs-probe disables this check, use at your own risk).
I also see a mount point and 2 disk systems. One is appears to be my debian install the other appear to be a install disk. I can't seem to figure out whee on the filesytem the install disk is. There is clearly only one partition.
I installed this by using VMWare and installing to usb rather then a disk in vmware. I have another usb that doesn't suffer the problem but I used a labtop instead