Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

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

This question already has an answer here:

I had Ubuntu 12.04 + Windows 7 installed, I didn't like Ubuntu hence I deleted the partition. But I forgot to fix the MBR. Also I cannot access the mutiboot option using F12 at startup. So when I start, I get the Lenovo screen with F2, F12 options but none work, and then the screen shows:

unknown filesystem
grub rescue-

with commands ls I get:

(hd0) (hd0,gpt6) (hd0,gpt5) (hd0,gpt4) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (cd 0)

and with set I get:


may be because I had installed my Ubuntu in gpt3 partition

can anybody fix this problem?

share|improve this question

marked as duplicate by Karan, Brad Patton, terdon, Simon, 8088 Apr 24 '13 at 16:05

This question was marked as an exact duplicate of an existing question.

Possible related thread:… – C-dizzle Apr 23 '13 at 13:04
Is it a laptop or a desktop? Could we have any details on your motherboard/laptop manufacturer? – gronostaj Apr 23 '13 at 13:23
It could be F1 or F10 or Del. – Alvin Wong Apr 23 '13 at 13:23
MBR is a fully separate issue from Bios access and is unrelated. Try spamming the F2 key on boot (hit it repeatedly from boot until you're in bios or back and grub rescue and report back) to see if it just isn't registering right. Is it safe to assume when you reach grub rescue your keyboard is registering keystrokes? – nerdwaller Apr 23 '13 at 13:30

I would load the Windows installer DVD into the DVD tray, and change the BIOS to boot from it. That's what did it for me when I had the same issue.

share|improve this answer
So, to explain the downvote: First you are overlooking the issue that they say they "Can't access bios" (even though the issues are unrelated to MBR). But beyond that, Super User wants questions to be relevant for future users, so it would be helpful for you to explain what to do next if the OP could get the Windows disc booted. It may seem obvious to some, but not always the case. – nerdwaller Apr 23 '13 at 13:51

Not the answer you're looking for? Browse other questions tagged .