windows 7 - Is it possible to repair the boot sector on an external hard drive?

Is it possible to repair the boot sector of an external hard drive

1. without a Windows installation disk,



2. without any CD-burning capabilities,


3. and without a USB key drive?

In other words, I have an external hard drive with Windows 7 on it, hooked up via USB on a hard drive dock, whose MBR I want to fix. I imagined simply downloading a utility, running it, selecting this external hard drive (A:\), and hitting "Go." So far, I haven't been able to find such a utility.

Why?

My only USB memory stick appears to have called it quits, and I don't have any blank CDs to burn. I have a genuine Windows 7 installation disk, but I get this error when I try to enter the "Repair" option:

This version of System Recovery Options is not compatible with the version of Windows you are trying to repair.

Background

I just wanted to upgrade from my 250GB SSD to a 750GB SSD—both happen to be the same make and model, in fact.

I used EaseUS Backup, selecting the "Optimize SSD" and "Sector by Sector" options. It finished in about an hour.

When attempting to boot from the new drive, BIOS did detect the device, listing it under bootable devices, but selecting the device only led back to the boot menu.

I read that cloning can fail under certain conditions, but that usually fixing the MBR would resolve the issue. So all this time, I've just been trying to fix the MBR on the new drive,.