NickC wrote:Completely fresh install of wheezy now completed. But won't even try to boot due to a GRUB error!
What error message is shown?
NickC wrote: Is there some way to reinstall the GRUB bootloader only,
There are many ways.
The shortest way may be to use Super Grub2 Disk.
http://www.supergrubdisk.org/NickC wrote:I have booted from Knoppix and established that I have the following partitions:
/dev/sda1 - ntfs
/dev/sda2 - ntfs
/dev/sda3 - extended
/dev/sda5 - ntfs
/dev/sda6 - ntfs
/dev/sda7 - ntfs
/dev/sdb1 - ntfs
/dev/sdb2 - extended
/dev/sdb5 - ext3, boot
/dev/sdb6 - linux-swap
/dev/sdb7 - root?
What do I need to do to install GRUB to /dev/sdb5?
If you install Grub2 code onto the partition boot record of /dev/sdb5, you may be unable to boot Grub2 directly.
First, BIOS try to find the bootable device (usually, MBR of /dev/sda, /dev/sdb). The order can be set by BIOS configuration.
You should configure so that partition boot record of /dev/sdb5 is chainloaded.
Instead, you can install grub2 code onto MBR of /dev/sdb or /dev/sda. It is simpler for especially a newbie.
But be careful! You do not mention about the OS's installed on your two hard disks.
If /dev/sdb contains some boot loader, installing grub2 code onto the MBR of your second hard disk (/dev/sdb) destroy the boot loader in the MBR.
I do not know about Knoppix. You do not mention version of Knoppix.
Maybe you can install grub2 code by using your knoppix, though I am not sure.
If you cannot solve the problem by yourself, execute boot info script while knoppix is booting, and post the contents of the generated RESULTS.txt.
boot info script:
http://bootinfoscript.sourceforge.net/