GRUB boot sector destroyed

[Shompol]

I installed Ubuntu as a dual boot with existing Windows 7, the next day the boot sector is gone, most likely corrupted by a windows trojan or a rogue app.
Needless to say, the blame is pinned on me.

How can I restore boot sector with GRUB?

[lazyworkhorse]

Why don't you try reinstalling ubuntu. You can tell it to preserve your home folder, and (I think) it will reinstall grub properly. Before you do anything, see if there actually was a badware on the system.

[oldfred]

How to restore the Ubuntu/XP/Vista/7 bootloader (Updated for Ubuntu 9.10)
http://ubuntuforums.org/showthread.php?t=1014708
https://help.ubuntu.com/community/Grub2#Reinstalling%20from%20LiveCD


Grub team looking for info:
http://www.chiark.greenend.org.uk/ucgi/~cjwatson/blosxom/debian/2010-08-28-windows-applications-making-grub2-unbootable.html
http://sourceforge.net/apps/mediawiki/bootinfoscript/index.php?title=Boot_Problems:Windows_Writes_To_MB R
http://www.supergrubdisk.org/wiki/WindowsErasesGrub
http://linux.slashdot.org/story/10/08/28/2112208/Some-Windows-Apps-Make-GRUB-2-Unbootable
In Windows 7, I had to remove Windows 7 DataSafe.
HP ProtectTools, Dell Recovery, and a few others write into MBR meierfra.
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/441941
https://bugs.edge.launchpad.net/ubuntu/+source/grub2/+bug/441941?comments=all
Dell Media direct or Uninstall Dell DataSafe issues with MBR
http://ubuntuforums.org/showpost.php?p=9330849&postcount=9