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I boot up to Windows 7, clicked on START, and right click on Computer and chose "Manage", and then I right clicked on a primary partition which wasn't the partition for C: but just a useless partition instead. (I repeat: it is NOT the partition for C:. It was G:).

After I right clicked on that useless partition, I chose "Delete" and confirmed I want to delete.

Then after 30 seconds, Windows 7 blue screen, and I cannot boot up Windows 7 any more. The suggestion on screen is that I boot up Windows 7 from the DVD-ROM, chose Repair, but it didn't repair it. The repair tool showed the Windows 7 partition is 0 MB. If I boot up to Vista instead, and chose Disk Manager, it showed the Windows 7 partition now as "Free Space".

How can I get back Windows 7 (with all the data)?

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Some people didn't believe me when I said the disk manager still has bugs like this. The first step: Don't make a new partition in there! (Unless it's a recovery tool telling you it's found the old one in there with the correct size.) – Mehrdad Apr 24 '12 at 6:00

Are you sure you deleted windows partition from running windows? I don't think windows is dumb enough to let you do that.

Here's what you can do:

  1. Check which partition you actually deleted(Open each partition in explorer and see the contents)
  2. If you have actually deleted windows partition, you are pretty much out of luck when it comes to data.(You can try some professional data recovery tools that cost an arm and leg with no guarantee of recovery)
  3. If that partition(should have windows, program files etc folders) is still there, than its just boot issue.
  4. In that case, mark that partition as "Active" and "Boot" using any partition manager and then repair the startup(i.e. boot loader) using windows 7 dvd.

If this doesn't work, please paste a screen shot of your disk management.

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Yes, Windows is dumb enough to do that. It's hard to believe until it happens to you, though. – Mehrdad Apr 24 '12 at 5:53
@Mehrdad - You never were able to reproduce it, I am more inclined to believe, user error then a bug ( this big ) in a tool that has existed for over 15 years. – Ramhound Apr 26 '12 at 12:33
@Ramhound: I never said I couldn't reproduce it. It's happened to me multiple times. I just can't reproduce it deterministically. (And by the way, FYI, I know where I click, and when my selection suddenly changes to something 3 inches farther on the screen. And I know something is wrong when I suddenly get 750 GiB of unpartitioned space out of a 500-GiB hard disk. Though if you think I'm lying then I don't really have any incentive to prove you wrong.) – Mehrdad Apr 26 '12 at 16:26
@Ramhound: Another bug in Windows 7's disk management: (notice the primary partition in the middle) – Mehrdad May 13 '12 at 9:41

For partition recovery there are free tools - for example Mini Tool Partition Recovery is user friendly and I have recovered myself a deleted partition very easy. Use it from Vista - let it scan the disk and find lost partitions.

It is possible that if you delete one partition you loose more than one partition - the extended partition can hold many logical partitions which are chained one after the other. So if you loose one partition the chain of partitions is broken!

In the MBR (where the main partition information is stored) there is room for only 4 primary partition records maximum (or 3 primary and one extended partition records).

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Windows 7 is so careless as to delete one partition and then also lose another partition completely? I mean, this is one important feature of the hard disk, and we are talking about a whole partition of data lost... wow... – 太極者無極而生 Apr 24 '12 at 5:54
oh I searched for "Partition Recovery" on Google and found and also Mini Tool Partition Recovery, as well as DiskInternals Partition Recovery and EaseUS Partition Recovery. Do you know if they are good too or any alternatives? thanks so much – 太極者無極而生 Apr 24 '12 at 5:57
There are known problems between Windows XP and Windows Vista partitions as they are differently aligned - they start at different bounderies. If you create a partition in Vista/Windows 7 Disk Management in XP can delete these partitions when doing a simple "mark partition as active" !!! – snayob Apr 25 '12 at 0:02
@snayob: Are these "known problems" listed somewhere on MS's website? – Mehrdad Apr 26 '12 at 16:49
@Mehrdad: You can post a question on to get an answer from people which have experience with this issue. I don't know if Microsoft has described the problem but I can reproduce it every time I want on my own computer ! It is not very dangerous if you have expeience - NO INFORMATION IS LOST - just the partition information is wrong ! – snayob Apr 27 '12 at 14:18

I've found the free Easeus Partition Recovery tool to be great.

No matter what tool you're using, though: Make sure it's detected the size of the partition correctly before recovering it! If not, it might overwrite the data accidentally, which makes it a lot harder to recover the partition.

I would recommend you first try to somehow back up the first 5 gigabytes or so of the free space, before continuing (or at least, the first few megabytes)... I'll try and see if I can find an easy way way to do that, though, since it might not be easy.

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What's with the downvote? – Mehrdad Apr 26 '12 at 16:47

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