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Possible Duplicate:
Can't boot without Flash Drive plugged in

similar problem

My problem is very much like the problem described in the link.

I have FreeDOS and Ubuntu 12.04. When I boot without bootable USB the computer simply proceeds to DOS. With USB stick I have to enter ubuntu via BIOS.

I WISH TO REINSTALL Ubuntu. What is the procedure to reinstall ubuntu from ubuntu itself?

Or is there any other solution to the problem?

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marked as duplicate by Tom Brossman, hhlp, Takkat, Eliah Kagan, jokerdino Oct 7 '12 at 1:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

Agreed. There are quite a few of these. I suspect there is a bug that is causing the USB to be the default install location for the bootloader on certain hardware. – adempewolff May 28 '12 at 9:04
sudo grub-install /dev/sda && sudo update-grub

Running this code in the terminal solves the problem.

Thanks a lot to Adempewolff.

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You will find a guide here: How to Install Ubuntu 12.04 Precise Pangolin

Take care: at a certain moment the system will ask you where the bootloader must be installed. Not in the usb of course, but mostly on your hard disk (C drive) - sad1 (mostly).

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thanks. Will try it out and reply. – karthikeyan May 28 '12 at 8:21
the link you gave shows the procedure to install 12.04. But actually i have installed 12.04;the problem is with booting it. I need the bootable USB stick everytime i need to boot ubuntu – karthikeyan May 28 '12 at 8:26
@karthikeyan The reason Julien posted installation instructions is because your symptoms seem to indicate that you did not in fact install Ubuntu to your harddrive, thus you need to actually install it. It is also possible that you did install Ubuntu but forgot to install a boot loader. In either case reinstalling and making sure to install the bootloader on the Master Boot Record of your primary hard drive will fix the problem. When you use a USB to boot you aren't actually booting into an installed Ubuntu, you are just running a "sample version" off of the USB. – adempewolff May 28 '12 at 8:35
@adempewolff can you please help me now how to reinstall ubuntu?Because when ever i insert the bootable usb stick it takes me to GRUB display to select and enter inti ubuntu; there are no option of installing or reinstalling. – karthikeyan May 28 '12 at 8:36
@adempewolff also how is it possible to add a boot loader now? I am currently typing this from Ubuntu only... – karthikeyan May 28 '12 at 8:39

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