Formatted /system and now everything is messed up

[pandadunham]

Okay, so, I'm moderately good with cell phones and rooting and such, but today I completely messed up and I don't know how to get myself out of this hole I dug.

I was trying to run a new rom on my Galaxy S3, (MIUI) and I did the regular steps like installing from sd card, erasing cache, factory reset, blah blah, but after It didn't set in the first time, and folders weren't showing up on my pc when I connected the phone to it, I started to panic, I booted into recovery mode, and stupidly formatted system, sd card, and ext sd card, and after that, all chaos broke loose.

My phone was then stuck at the Samsung Galaxy SIII logo on boot, so I tried entering recovery mode because I thought I made a backup, but my phone would not boot up into recovery mode. It would only open to Odin mode, so, after a lot of crying, I downloaded stock touchwiz for d2vzw and used odin to use it. Everything was fine and dandy but then my root was gone, so I re-rooted it with a guide on youtube, (used it before and worked like a charm) and the root worked again, like i had expected. Now, I again, messed up and tried flashing miui because I was on LiquidSmooth but i couldn't figure out why it wouldn't let me install apps I had previously deleted, and now, I still can not boot into recovery mode without EZ-Recovery, but I can't even do that because I messed up the ROM loading AGAIN, I am so done with this and if I can just flash the latest GAPPS and CM10.1.2 I will be set for good forever. So please,I know there maybe holes in my story but I just want to fix my phone, and by now the warranty is so void it's not even funny. So anyone, if you have any thing I can do to fix this mess, I will be forever grateful.

 

[Golfdriver97]

Okay, so, I'm moderately good with cell phones and rooting and such, but today I completely messed up and I don't know how to get myself out of this hole I dug.

I was trying to run a new rom on my Galaxy S3, (MIUI) and I did the regular steps like installing from sd card, erasing cache, factory reset, blah blah, but after It didn't set in the first time, and folders weren't showing up on my pc when I connected the phone to it, I started to panic, I booted into recovery mode, and stupidly formatted system, sd card, and ext sd card, and after that, all chaos broke loose.

My phone was then stuck at the Samsung Galaxy S3 logo on boot, so I tried entering recovery mode because I thought I made a backup, but my phone would not boot up into recovery mode. It would only open to Odin mode, so, after a lot of crying, I downloaded stock touchwiz for d2vzw and used odin to use it. Everything was fine and dandy but then my root was gone, so I re-rooted it with a guide on youtube, (used it before and worked like a charm) and the root worked again, like i had expected. Now, I again, messed up and tried flashing miui because I was on LiquidSmooth but i couldn't figure out why it wouldn't let me install apps I had previously deleted, and now, I still can not boot into recovery mode without EZ-Recovery, but I can't even do that because I messed up the ROM loading AGAIN, I am so done with this and if I can just flash the latest GAPPS and CM10.1.2 I will be set for good forever. So please,I know there maybe holes in my story but I just want to fix my phone, and by now the warranty is so void it's not even funny. So anyone, if you have any thing I can do to fix this mess, I will be forever grateful.

I would reflash the stock ROM again. Since I can't view your root method, I would try this instead: How to Root Verizon Galaxy S3 SCH-I535! | Galaxy S3 Root
I linked to Verizon, due to you using the Verizon code for the S3 (d2vzw).
After that, you should be able to flash CM.

 

[srkmagnus]

Odin the stock ROM as you did the first time and start over. Read the instructions for ROM flashing carefully (often times requires wiping cache, factory reset, system) so you don't run into this problem again.

Let us know when you get back to stock.