Fix Mbr after performing clean command

Question

My laptop was in dual-boot mode with Windows 7 Ultimate x64 and Ubuntu 12.04. However, for a research purpose, I had to install windows 8 on it. Since the laptop was in GPT mode, I converted it (the entire disk) to Mbr during the installation using the command prompt. In the process, I used the clean command and now when I proceed to install Windows 8, it shows a single unallocated disk without any partitions. I guess, this is because the clean command deletes the partition table. Since I have some important data in the HDD, is there any way that I can recover my Linux and Windows 7 installation (or at least the Linux installation) ?

I have tried using bootrec.exe, Windows recovery DVD for start-up repair and MiniTool Partition Wizard, but was still out of luck. Please help...

Solution:

Thank you very much for all of you for guiding me through. I resolved the issue and following are the major steps I performed.

1. Use TestDisk to recover the partition table. Though the entire partition table was not recovered, the windows installation partition was recovered, but still it was not bootable.
2. Used windows repair tools to repair the startup procedure and WIndows 7 is now  bootable.
3. Now when I used Ubuntu Live USB to boot-up, it shows all the Ubuntu partitions, but still Ubuntu boot repair was a failure and gave the following error. 

"GPT detected. Please create a BIOS-Boot partition (>1MB, unformatted filesystem, bios_grub flag). This can be performed via tools such as Gparted. Then try again. Alternatively, you can retry after activating the [Separate /boot/efi partition:] option."

4. I logged into Windows 7 and installed EasyBCD free version and inserted a new Ubuntu boot entry to the recommended location.
5. Now, both OSs are working like a charm.

Thanks guys.

Answer 1

Important or irreplaceable files must at all times be stored in at least two independent places, preferably in several versions. Storage space costs less than it has ever cost before. Some cloud storage is even free.

Answer 2

Thanks a lot, I will surely try my luck using the aforementioned software. If I do not succeed, indeed it would be a very harsh lesson for me since it contains data related to my PhD. We'll see.

Answer 3

Thank you very much, though it's a bad news for me. It's a very bad day at office, I suppose.

Answer 4

For a research purpose, I had to install windows 8 on it.

-> The standard method is to create a "sandpit" environment by using a separate hard disk (whose cost is negligible).

It shows a single unallocated disk without any partitions. I guess, this is because the clean command deletes the partition table.

-> Correct.

Since I have some important data in the HDD, is there any way that I can recover my Linux and Windows 7 installation (or at least the Linux installation) ?

-> Very unlikely. You could try some of partition undelete tools that you will find with a Google search. If unsuccessful then you have to restore your important data from your external backup or from an image that you might have created of your partitions. If you did not then there are some harsh lessons to be learnt here. Sorry.

Answer 5

Clean command removes all the partition information from the HDD. Hence, you see a single unallocated disk.

It's not possible to recover any data as the partition information is lost.

You can Bing/Google for regarding recovery of data, but we can't guarantee the working.