I have a laptop with a faulty BIOS that has stopped booting from CDs even though it supports it (and it doesn't support booting from USB drives).

I am trying to install Ubuntu 10.10 on it. I already had 9.10 installed. I tried using Kexec, but it refused to accept the kernel image.

Eventually I found this page which shows how to make GRUB 2 boot from an ISO file.

That worked fine, and I am now running the live image from the file. (If I can get this to work, it will be my new preferred way of installing Ubuntu, as it saves CDs and boots much faster.) However, I can't install it.

The installer won't make changes to the hard drive, because the partition containing the ISO is mounted (and can't be unmounted because it is in use). Even if I only choose to use other partitions that are not mounted, the installer refuses to go any farther. Clearly, it should be possible using other partitions on the same disk.

Is there any way to work around this issue or force the installer to go ahead?