Changing Partition System

As WIndows tells me, "on EFI systems, WIndows can only be installed to GPT disks". This is the error message I get trying to install a Windows upgrade from 7 Home Premium to Pro. I have to do a custom install because I am installing English over Russian. I have looked on the internet about how to change my partition system to GPT. Seems like something I can do, however, I have a question:

If I have only one physical hard drive in my machine, is it possible the change the partition system from MBR to GPT? I see lots of examples of doing it to a second hard drive, but not many when it is the only hard drive. It is a new drive and clean, so I do not worry at this point about the data on it.
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  1. It is possible, but will wipe everything that is on the disk. You will have to delete all partitions before re-initializing the drive. Another problem is that, of course, you can't do this with the OS on the drive!

    You will probably have to download a bootable distro that does partition management and can handle GPT (I haven't done GPT, so I can't tell you the name of a utility that will do this for you). Burn it to a CD, then boot from the CD, nuke your drive, and re-initialize it as GPT.

    You will have to restart the install from the beginning, not as an upgrade.

    EDIT: EASEUS claims that it can do the re-initialize step:
  2. According to the software I use to modify partitions converting MBR to GPT can only be done to a disk with no partitions. Believe you would then create partitions afterwards.

    Software download here
  3. You can always use a live CD to delete all partitions, then run the windows installer and let the windows installer create the new partition as GPT. This may also be safer since windows 7 knows how to align sectors on both old and new drives using advanced format.
  4. ...and you could also using disk cloning software to backup the existing installation, then delete the partitions, recreate the disk as GPT, intitialise it, then restore the system back into the current state from the backup image. Just a suggestion, but if you don't have somewhere to backup the OS disk, then this might be difficult, as I normally use a data disk in my system for OS backups, after booting the machine from a linux based USB key, then using Acronis, which is as commerical product.

    For freeware disk imaging, have a look here, but I can't recommend any of them, as I haven't personally used them:
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