[all variants] dual boot windows ubuntu without windows CD

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http://ubuntuforums.org – Hi, I have a lenovo thinkpad X230T that came with windows7 installed. Before wiping out the disk and doing a fresh linux installation I wanted to make a dual boot for a while. The problem is that I don't have any windows CDs to repair the MBR after installing grub because windows was preinstalled. Any suggestions on what to do? thank! (Hardware)