OK...download and install 7Zip. It is a program that unzips compressed files. You can find it on CNET . com. You will need this program. Next, go to rilco12 . com. Click Downloads>Galaxy S3 (SPH-L710)>Stock ROMs>JB>MD4>No Data Restore>Unrooted. Select the .exe file. When it is downloaded, create a file folder and rename it to MD4 on your desktop and move it from your Downloads folder. Open 7Zip, and You will have to navigate to your file in question, most likely Computer>C:/>Users>Your PC User Name>Desktop>MD4. Highlight the file and click on the blue minus button labeled Extract.
You will get a new window, and the file you clicked will be highlighted in blue. Next to it should be a box with 3 dots in it. Click on that and another window will come up with your files on it, scroll down to the MD4 file, and click on it once to highlight it. then click OK. Let it decompress everything, and you will find a folder called ODIN OC meaning Odin One Click. Open that folder. You will see a program in it. Double click on that and another window will come up with MD4 Stock Restore on it. Power down your device, but make sure you have at least a 70% charge. You will power up in Download mode, which is Volume Down, Home and Power at the same time. A warning will come up giving you a choice to push volume up or down. Push Volume to Continue. Connect your charging cable to your PC, and on your screen the Odin window will show one of the boxes to say COM and a number. Your PC may have to load drivers and talk to the phone for a few minutes, maybe up to ten, but once you plug in your device, DO NOT UNPLUG IT. Once it says the COM and a number, click the big start button on the bottom. This will start to flash the new ROM. This also may take about ten to fifteen minutes. Be patient. When it's done it will have a green box saying pass, and you can unplug your device.
Read this a couple times. If you have any questions you can PM me.