How timely. I just spent 2 hours re-installing grub2 after Windows wiped it out (I knew it was going to happen but I hoped it wouldn't be any trouble to restore it). As I use LVM, I had to copy the /dev/dm-* devices to /dev/mapper/<lv>-<vg> in order to install grub (this is what took 1h50mins to figure out). Then I had to boot in to Ubuntu and update the grub config again to pick up Windows.
That said, Ubuntu has improved a lot and despite the grub issue, I still love Ubuntu. I have converted both my parents to Ubuntu and I haven't had a support call from them since the switch.
Actually, it's pretty simple. Boot a DOS disk. Run 'fdisk /mbr'.
Mind: my preference would be booting FreeDOS, not some borken Microsoft crap. But all the same.
My experience is that fixing Linux GRUB issues is also pretty straightforward. Helps to understand chroots and stuff, but still: boot a bootable distro (Ubuntu or Knoppix on a USB stick rawks), chroot into your installed root FS, mount /boot if necessary, and run 'grub-install' or 'update-grub'.
I know, I just happen to be using Ubuntu. However, 99% of users will blame Ubuntu. (I think the issue is already fixed in newer versions of lvm2 (or grub2, I can't remember which they patched.))
Am I missing something with Windows? Can it detect non-Windows partitions? How can I fix it?
That said, Ubuntu has improved a lot and despite the grub issue, I still love Ubuntu. I have converted both my parents to Ubuntu and I haven't had a support call from them since the switch.