Get the installation disk for your Linux distro, insert that into the CD/DVD/BRD drive while in Win 7 and reboot. Once it's up, choose the option that allows GRUB to be installed. When you do this, it should detect your Linux partition and correctly list it every time the PC boots up.
I had Windows Vista and Linux on different partitions of my C:\ and everything (dual booting) was fine. Recently I overwrote Vista with Windows 7 without formatting. But now the boot menu doesn't show Linux even though I know it is there and not corrupted? How do I edit BRUB/MBR to recover Linux? My computer now boots into Windows 7 only

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