Can't boot Ubuntu

Question

I've installed ubuntu using live CD. But when I turn my computer on, it starts windows 7 instead of giving me right to make a decision, which OS I need to boot. I think I have some problems with GRUB - it isn't run.

Answer 1

If you installed using a USB then try booting with the USB connected, if you see grub and can boot Ubuntu then have a look at this guide on our website for details of how to resolve the problem. :o)

Let us know if it helps.

Answer 2

Grub organises two OSs on one Harddrive, you seem to have W7 in the harddrive and Ubuntu on a CD - so tell your BIOS to boot from CD.

Answer 3

Step 1 - From a Ubuntu Live CD

Open up a Terminal by hitting Ctrl Alt T; we'll run a few commands.

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First, identify which is the Ubuntu partition:

sudo fdisk -l | grep -iR linux | grep -viR swap

This should return a line like the following:

/dev/sda1   *          63    77144129    38572033+  83  Linux

• In this example, the partition identifier is /dev/sda1.

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Mount this partition.

sudo mount /dev/sda1 /mnt

• Replace /dev/sda1 with the partition identifier you identified earlier.

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Reinstall Grub.

sudo grub-install --root-directory=/mnt /dev/sda

• Replace /dev/sda with the appropriate hard drive identifier. This is the Ubuntu partition's identifier, without the trailing number.

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Reboot your computer, this time without the Live CD.

Step 2 - From the installed Ubuntu

If all went well in the previous step, you should now be logged into Ubuntu.

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Once again, open up Terminal by hitting Ctrl Alt T.

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Now, run this:

sudo update-grub

This should detect your Windows installation and automatically add it to the Grub menu.

You're done!

Reboot.

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To make the Grub menu show up if it doesn't by default, hold the left Shift key during the boot-up process. You'll then be able to select which OS you'd like to boot into.

Answer 4

Use Boot-Repair's Recommended Repair to reinstall GRUB in 1 click. It will also provide a BootInfo summary if you need more help.