How can I install Windows 7 from an external hard drive?

I followed the instructions here, but

format fs=fat32 quick

did not work, it gave the following error:

Virtual Disk Service error:
The volume size is too big.

So I then tried just format quick which worked.

Now, will I be able to install Windows 7 properly if I copy the root contents of the Windows 7 install disc to this external drive and then boot off of it?

Solution 1:

There is a fairly easy way to install Windows 7 from an external hard drive, and it takes less then 10 minutes to set up. You also don't need to switch to FAT32 to use this method.

First, format your disk as NTFS (quick format is fine, default sector size). Then, extract your Windows 7 disc/ISO to the hard drive. There is a utility included on the Windows 7 disc which allows you to mark the drive as bootable, located in the boot folder.

Once you're there, run BOOTSECT /NT60 X:, where X: is the letter of the external hard drive. Once that's done, you can just plug the drive into your computer, and you should be able to boot from it. Just FYI, the BOOTSECT tool updates the MBR for that drive's partition.

Alternatively, you could also just run the following command (from a command prompt or from the Run dialog, WinKey + R):

X:\boot\BOOTSECT /NT60 X:

Where, again, X: is the drive letter of your external hard drive. Once this is done, the hard drive has been marked as bootable, and if you try to boot your computer from it, the Windows 7 installation will be launched.

The reason they use FAT32 in that Technet article you posted is because those instructions were for a USB key. You can follow the DISKPART part of that guide to get your partitions prepared and setup, but do ensure that you format the drive using NTFS.

Solution 2:

I'd check to make sure that the fs on the USB HDD is fat32. If it is, than you should have no problem continueing. If it isn't though, I'd suggest re-partitioning it into a smaller chunk and only using that bit (make sure it's boot flag is set).

Solution 3:

I found how to boot Windows 7 on an external hard drive by using a program called PWBoot.

All you have to do is install Windows Vista or Windows 7 by connecting the drive on ata or ide. Then, after the installation is over, you boot into Windows and install the program PWBoot. From that moment on, your hard drive will be able to boot from a USB.