Dual boot Windows XP and Ubuntu: XP won't boot.

[Markus Schönhaber]

Dotan Cohen:

> Windows is on sda1 and Ubuntu is on sdb1, with Grub on sdb and
> the BIOS configured to boot from sdb. Before the install, BIOS was
> configured to boot from sda, which was the existing Windows install.
> 
> Upon startup, the computer gets to the Grub screen just fine, and if
> the user selects Ubuntu then the computer boots as expected. However,
> if the user selects Windows then he gets a black screen with the text
> "Starting up...". This screen does not change, I have waited over an
> hour to see if it would continue. However, if I change the BIOS
> setting to boot from sda then Windows boots up fine. I tried changing
> the Grub boot configuration for windows from (0,0) to every other
> logical value, but Windows would not get past that "Starting up..."
> screen.

My guess would be that Windows gets confused from not being on the first
(BIOS) disk any more as it was when installed.
Maybe it's as easy as changing the mapping of the drives, i. e. adding
map (hd0) (hd1)
map (hd1) (hd0)
to the Windows entry in GRUB's menu.lst.

If that doesn't work, what I'd do (from memory aka untested):
- Reset the BIOS to boot from the Windows disk,
- install GRUB in the Windows disk's MBR with root pointing to the
appropriate partition on sdb/(hd1),
- create an entry in GRUB's menu.lst that chainloads Windows, something like
rootnoverify (hd0,0)
chainloader +1
should do if Windows is installed on the disk's first partition.

An alternative could be:
- Reset BIOS to boot from Windows disk,
- install GRUB in some other location - for example the MBR of the
second disk,
- copy the second disk's MBR (or at least the part containing GRUB's
boot code) to a file on the Windows partition, say C:\linux.bin
- add an entry to XP's boot configuration file C:\boot.ini like
c:\linux.bin="Ubuntu Linux"
This way, XP's boot loader should give you the option to start your
Linux install.

-- 
Regards
  mks