I'm working in Windows 7 and trying to create a bootable Windows 7 partition. I'm working with a computer with no optical drive and the only USB device I have is a 2TB external HDD with a bunch of data. It has 2 partitions, the first is NTFS with my data, and the second is empty and 20GB large. I've tried formatting the 20GB partition as FAT32 and marking it active, but UNetbootin and Windows 7 USB/DVD download tool cannot seem to find the partition.

I don't want to move all my data. Is only the first partition eligible to boot? Can I make the bigger partition with all my data have the Window 7 boot data without moving all my files? Is there a way to make the second partition bootable?


Actually you can do.

Goto your Disk Management (Hope you know the Disk Manager) or Type DiskMgmt.msc in Run

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Now you can see in the 1st Row Disk0 shows as Dark Blue Border, it means it is Primary Partition. and rest of them are in green border. it's called Extended Partition.

I guess your 2nd Partition is Extended. because you cannot boot from extended partition. all bootable partitions should be Primary.

1) All you have to do now is, open the DiskMamagement and Right Click on the 2nd Partition and Delete it. so it will become full black.(you need to delete twice)

2) now in the RUN type CMD (Command Prompt). and type again Diskpart Press Enter

3) in that, type List Disk that will show you the Volume list so select the appropriate Disk by typing Select Disk 0

4) now type again. Create Partition Primary

5) after that type again to format the created volume Format FS=NTFS Quick

and That's it. now Windows 7 DVD Tool will Detect your Partition

  • Wow, thanks! I was seeing recommendation for FAT32. Does it matter? – Stuart Dec 16 '13 at 21:04
  • Can I have multiple primary partitions OR is it just that I don't need my data partition to be primary? – Stuart Dec 16 '13 at 21:22
  • No Problem, you can set it FS=FAT32, but i would suggest NTFS if you ask me – Kirk Dec 17 '13 at 5:52
  • of course you can have, but not more than 4 Primary partition is allowed. meaning, normally you can install only 4 OS. having the files in Primary partition is no issue. just the difference is primary partition is to handle OS's that's it – Kirk Dec 17 '13 at 5:54
  • You say "OS", but I am putting an OS install on that partition, not an actual OS. By OS, do you mean anything that can be booted to? – Stuart Dec 17 '13 at 23:00

For the sake of those that only have a single partition like I did, that you dont want to delete/format, you can shrink your existing partition with a 3rd party tool (I used one called AOMEI Partition Assistant, but there are several others).

Once you've done that you can pickup from step 2 of @Kirk's answer to format that new partition (note, you dont have to select the partition, the diskpart utility apparently knows thats the one you want to perform operations on).

Once thats done, to complete the setup for a boot disk;

  1. Assign the new partition a drive letter ("assign" command in diskpart utility)
  2. Mount the ISO youd like to install onto a virtual cd rom (using a tool such as PowerISO)
  3. Make the external drive bootable and copy over install files from mounted virtual cd rom to the now bootable external drive partition

Details instructions are listed here; http://bootableusb.net/make-bootable-external-hdd-install-windows-78/

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