Yesterday when I install a driver for USB (I think it was udev or similar... ), but when I try to instal the USB-driver with Synaptic it say's I must uninstal AMD64..xxx.xx..xx...something...
I accept to remove this and install the USB-driver.
But, when I should reboot the system is could only boot on MS Vista partition !
I have only one alternativ in the grub boot, so I could only boot MS Vista.
I boot the PC on a Knoppix CD and notice that the file /boot/grub/menu.lst was changed !
I try to change it, but I have only read access.
Then I realize that the device /media/sda3 must be mounted with "write-acesss", so I change mount with write access for sda3
but still I could not change the file.(only file read-access)
I try to start a root terminal, but then Knoppix ask after a password !
Have have not any root password when I boot Knoppix from a CD.

How should I get write access to the file menu.lst ?

/Ulf

PS
I have a CPU AMD64 dual core with one harddisk.
I using grub with dual boot for MS Vista and Debian Linux AMD64

In knoppix you need to assign a root password. Type passwd root press enter, then input the root password you would like to use.

Okey, it works ! (but NOT...)
Now I login as root-terminal (+ password) and get the prompt
root@Knoppix:

The device sda3 (under /media/sda3) is mounted with read-only disable, but still I can't change the menu.lst file.
If I have the cursor over the sda3 device on the desktop I could verify the sda3 device is writable.

But, still no files on device sda3 (/media.sda3.../ ) could be changed.
Here is the protection of the sda3 (with ls -all )
drwxr-xr-x 25 root root 4096 Jan 4 03:07 sda3

What's wrong ?