grub windows 7 and 8 dual boot.

http://askubuntu.com/questions/135272/how-to-boot-into-windows-7-when-grub-is-installed-in-the-windows-partition

A possible work-around to boot Windows 7

Below is a suggestion for editing your GRUB boot commands which may allow you to boot Windows 7. I am not sure this will work, but it seems worth trying.
Currently your grub.cfg uses the GRUB boot commands below to boot Windows 7.

menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos1)'
    search --no-floppy --fs-uuid --set=root 1EA0019AA0017A13
    chainloader +1
}

I am suggesting you try changing this and use these commands instead.

menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    insmod ntldr
    set root='(hd0,msdos1)'
    search --no-floppy --fs-uuid --set=root 1EA0019AA0017A13
    ntldr ($root)/bootmgr
}

Here are the steps to do this.

1. Boot your system to the GRUB menu.
2. Select (highlight) the GRUB boot menu entry Windows 7 (loader) (on /dev/sda1).
3. Press e to edit the GRUB boot commands for Windows 7.
4. Make two changes to this list of commands as illustrated in the menuentry above.
   • Add the command insmod ntldr
   • Change the command
     chainloader +1
     to
     ntldr ($root)/bootmgr
5. Press either Ctrl+X or F10 to boot using these edited commands.

Note 1:
If the above work-around succeeds in loading the Windows 7 boot menu, then you could make it semi-persistent by

1. Using sudo to edit the file /etc/grub.d/40_custom and add the second, modified menuentry shown above. (If you do this, I'd also suggest you change the title of this "custom" entry.)
2. Run the command sudo update-grub to update /boot/grub/grub.cfg to include your customized entry. (It will be on the bottom of the GRUB menu when you boot.)

I would view the suggestion above as only a partly-baked solution. A better solutions is to restore the Windows VBR to the Windows partition without also destroying the ability of GRUB to boot.
I think ... but am not 100% sure ... that the Windows recovery command bootsect can be used to do this. If you want to risk it, one possible way to do this is outlined below.

• When booting Windows, press F8 to bring up the Advanced Boot Options menu.
• Select the Repair Your Computer entry.
• Walk through the next windows until you reach System Recovery Options.
• Select Command Prompt
• Run the command bootsect /nt60 C:

But you might also want to wait a bit and see what other answers you get to your question before you take the risk of trying the above.
Note 2:
While searching for other things, I ran across two other questions on AskUbuntu which are related to your problem.

1. Windows 7 won't boot after installing Ubuntu 11
2. Windows 7 doesn't boot after Ubuntu install

I'm not sure how much help these questions provide. The answer to the second question was to use the command bootrec /fixboot to restore the VBR for the Windows partition. My understanding from that question was that using the bootrec /fixboot command solved the problem.
But the second question insists that bootrec /fixboot did not solve the problem.
(Beats the heck out of me as to what might be going on there.)