Recently, I messed up the installation on my son’s machine. I removed the first partition and did not adjust the boot loader. This left Windows 7 (2nd partition) unbootable. I spent some time running through tests and trying to figure out why the system would not recognize the volume. I could see it was there when booting the ‘other partition’ Lucid Lynx. However, the Grub loader did not have the entries for Windows 7. Instead of editing Grub loader, I opted for the Windows approach. After all, I had the startup repair disc. Here goes…
Sometimes the partition in question is not recognized by the WinRE (Windows Recovery Environment) or you receive “missing operating system”, “Bootmgr is missing”, or something comparable. In this case, you need to load the Startup Repair disc. See the link below:
Insert the Startup Repair disc in the drive and press the F8 (most machines) key during boot. This will open the menu to choose which drive to boot from: select the DVD drive on your machine.
Load the Startup Repair disc and select “Next”. Once you have arrived at the window below, select “Command Prompt”.
If your Windows 7 installation is not listed, then you need to click on the “Command Prompt” and enter the following commands below:
Type DISKPART at the command prompt to enter into this mode: ‘help’ will list the contents.
Next, type the commands below for information about the disk.
Next, type the commands below for information about the Windows 7 partition and to check whether or not it is marked as ‘Active’.
If the partition is not marked as Active (Active=Yes), then type ‘active’ at the prompt to mark it as active. ‘Active’ status is important because Windows 7 looks for the ‘active’ partition for WinRE (Windows Recovery Environment needs to recognize the system volume).
You can close the command prompt window and reboot. Run the startup repair disc until startup repair does not report any errors. This can take up to several runs. Then boot normally.
You should be back to normal. If not, then it’s time to look at alternatives like a clean install.