I have installed Ubuntu and i am unable to open windows it says windows Grub missing re-install system32. I don't want to lose data in windows please tell me how to install Grub(windows xp sp2).

Thank u

Can you boot ubuntu?

I can boot ubuntu.

Windows is already installed in my laptop, after installing ubuntu unable to boot windows.

Take a look at this document. About halfway down, there is a section on "what if Grub2 does not list windows". There is also a section for if you are using legacy grub. If you are using a current version of Ubuntu, it will be grub2, which you can identify based upon whether or not you have a menu.lst in you /boot directory (btw, grub2 does not use it, grub1 does).

If you have grub2, it should be a simple matter of typing in a terminal prompt:

Hello Noway2,
my question is how to recover windows after installing Ubuntu??
and you replied how to recover ubuntu after installing windows?

It locates windows boot loader. Sometimes it'll miss it during installation.
You can however repair wins with disk then reinstall grub afterwards.

in order to avoid losing all your data, you should mount all the windows partition in linux and copy the data to any external storage device...

@sattarkf, the document that I referenced is about manually manipulating and updating Grub. Specifically, I mentioned the sub section titled: "what if Grub2 does not list windows". Grub should identify the Linux AND Windows partitions. The section of the document I pointed to shows you how to run the Grub update and as long as you have an identifiable Windows partition on your hard drive(s), this should fix your problem. If this does not fix your problem, it is a strong indication that the boot sector on your Windows partition (that part that contains ntldr) somehow got messed up. In this case, you will likely need to do a Windows repair. This will overwrite (erase) your Grub boot loader. You will then need to follow the directions at the top of the document on how to recover Ubuntu in Grub after installing Windows.