I have installed Ubuntu 12.04 (daily-live iso from 21.04.12) alongside Windows 7 on an HP EliteBook laptop.
The installation went fine, except that it installed grub onto my usb disk (/dev/sdb) instead of the hard disk (/dev/sda). I was able to boot into the Ubuntu installation by using the usb disk which had grub installed on it. I then installed grub manually onto the hard disk (/dev/sda) by running "grub-install /dev/sda".
After I do that, I can book into either Ubuntu or Windows 7 from the Grub menu. However, after booting into Windows 7, grub doesn't load on the next boot. The computer simply reboots again and again, without giving any error. The screen simply goes black and reboots. There are two entries for Windows 7 in grub: for /dev/sda1 and /dev/sda3. These are in reality a single Windows installation which uses both partitions. Booting into either of them produces the same effect.
If I boot into the Ubuntu partition using the usb disk, I have found that I can restore grub to working order by using the boot-repair application. Then if I boot into Windows again, grub breaks again.
Full details of the log file which boot-repair produces, showing the partition details, are here: http://paste.ubuntu.com/940155/
Any ideas?