Problems with rooted s3 neo GT-i9301i

[k0fa]

Hello.

I have a few problems with my phone. Rooted s3 neo gt-i9301i with custom ROM manager - Cwm v5.5.3.7 .After connecting it to a PC via USB cable it charges, but it won't really connect. Drivers start to install but after a minute, maybe less an error is shown. My question is what do i have to do to restore my phone to factory settings - Stock rom, stock firmware, unrooted. It seems that i cannot connect my phone to my PC because MTP USB driver cannot be installed. Quite a lot of system apps are missing too, including the bluetooth.I dont't really care about the system apps(exept the bluetooth), but i need to use my warranty and also would like to be able to connect to a PC. Thanks in advance and please don't be to harsh on me. phone was stolen and i got it liek that after a month. Also i don't really know how to unroot it and flash stock firmware etc.....i just looked up online how system apps were removed and found out what was going on. Also there are apps like
-superSu
-Titanium backup
-ROM toolbox lite - after oppening it i found the version of the custom ROM
-Greenify

Maybe those are apps that have something to do with this....

 

[Rukbat]

Assuming you can't boot to Download, remove the battery. Hold power, volume down and home buttons for about 10 seconds. Replace the battery. That should boot you into download mode, with the warning screen. Hit the volume up button to go to download. Then follow [Samsung] How to flash Stock ROM via ODIN to flash the stock ROM.

 

[k0fa]

Thanks for the fast reply. But how does this work with removed battery ? Also phone does not connect to my PC, it just charges. Does this matter when in download mode ?