Need help getting external USB 3.0 drive with Windows 7-64-bit to boot

I was able to boot into Windows 7 Ultimate 64 bit, and now I am getting the message stating:

Windows Boot Manager

Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:
1. Insert your Windows installation disc and restart your computer.
2. Choose your language settings and then click "next."
3. Click 'repair your computer'.

If you do not have the disc, contact your system administrator or computer manufacturer for assistance.
File: windows\system32\winload.exe

Status: 0xc0000225

I know I have the full version of Windows 7 Ultimate 64-bit and I know the file winload.exe is on that drive to. I saw it. I had cloned the drive I have inside the external case to a bigger SSD drive that is now in my computer case so I can go to a full version of Windows 8.1 while still being able to boot into windows 7 on my external SSD drive that I have hooked to the USB 3.0 port. I bought one of those external case kits that let you use an SSD drive to migrate, copy or clone to another source or drive. Since it is an external drive the only way I can get it to boot is by going into UEFI Bios and selecting it as the drive I want to boot into, which was fine, and it worked a couple of times. Now I cannot even boot it up anymore without the windows boot manager error screen and message. I have tried everything, even copying the whole Windows 7 install DVD to the drive and nothing works. It won't allow me to repair anything necessary so it boots up. What do I do now? I have games I have played for weeks that will be lost due to the fact I have saved progress. I appreciate all the help I can get

Because I have been using nothing but Windows and building computers for years. It is easy. You just clone the drive already inside the computer using Samsung Data Migration software using a USB 3.0 case you pop the new drive into. Then you take the old drive out and put it in the same case, and just plug the old drive into the USB 3.0 port using the same case. You just set it in BIOS as your boot up drive and it worked. I found out what I did and fixed it. now it boots up from the USB port whenever I want it to :) although now that I transferred all my files I need and version 7 is outdated with Windows 8.1 being better, more secure and up to date, I am just going to erase the drive and use it for backup. wallah! thank you for your time. I just wanted a bigger SSD drive before I went to the full version of Windows 8.1 and I wanted to clone the drive to verify the integrity and working order of the new bigger capacity drive I bought. And when Windows 10 comes out in non beta full consumer build and sale I am going to upgrade to that to. People should always use the most current version of Windows and Internet Explorer, and use Malwarebytes and keep everything up to date.for obvious security reasons and being up to date. Every new version upon release should always be seen as crucial. People just don't get that and this is why so much hacking and identity theft is going on. You should also use a password manager and USB security key, which encrypts your passwords in Internet Explorer 11 so you sign into the browser, and then you change your passwords at least every 3 months. I recommend Last Pass. I have not had one virus or malware really ever. Thats why! Take care and Merry Christmas!

What were the speeds like running Win7 from USB3? The few who were able to do this on external with USB2 reported it was slow as molasses. A USB controller is normally a throttle compared to internal SATA.