Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I first installed Windows 7 ultimate onto my machine and using Windows 7 built-in partitioning system, I had partitioned my disk into many smaller disks of NTFS file systems. I then tried to install Ubuntu 12.04 onto my machine.

I had installed Ubuntu and Windows 7 side by side because I needed both the operating system but while booting I was getting an error as

Attention out of range
H:92.6KHz  V:58.2Hz

I was not getting any dual boot menu no msg was seen except the above message. I tried to press the down arrow thinking that it might take me to the option. First time it directly logged into Ubuntu then next time Windows 7.

When I logged into Windows 7, I deleted the volume in which Ubuntu was installed. Now, I am getting the error as

error:unknown file system 
grub rescue>

I want Windows 7 back and a better way to install both operating systems. Please give me some help in this regards.

share|improve this question
Take a look at this: – Mitch Jul 25 '12 at 19:07

If you have a Windows CD you boot your PC from it and you go to Repair. There you will see the option to open the CMD.

In cmd you type this 2 codes:

bootrec.exe /FixBoot
bootrec.exe /FixMbr

And you will get your Windows boot back. After that just try reinstalling Ubuntu as usual and it should work.

share|improve this answer
after trying this two commands i got an error as A disk read error occured to (some unidentified ascii characters) – A palekar Jul 26 '12 at 16:07

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.