I used to have windows xp on my first partition and ubuntu on my second. dual boot used to work fine with that configuration. a boot menu used to appear to select windows xp or ubuntu.
But, today I decided to replace xp with windows 7. So I inserted win7 DVD and reboot the computer with it. Formatted my first partition and installed windows 7.
Now, only the windows 7 boots, and no multiboot menu. the multiboot menu is gone.
I can still see the second partition in Windows 7( but not the files, only the space assigned to it), but I can not boot the unbuntu.