[Q] Please help!!

Hello guys!!
I really need your help because despite all that searching i can't find excactly what I' m looking for. I' m really sorry if it will sound silly!!

So there has been 2 years now that I have my galaxy s2. I ordered it from internet so If i'm not wrong i think it came from hungary.
The info from the phone is
Model: GT-I9100
Android version: 4.0.3
Baseband version: I9100XXLPQ
Kernel version: 3.0.15-I9100XXLPQ-cl223505 SE.INFRA@SEP-94#3
Build Number: IML74K.XXLPQ

PDA: XXLPQ PHONE: XXLPQ CSC: XXLPD

So after A LOT of changing roms and everything i decided to return back to the stock rom/firmware/kernel i don't know excactly which one is correct... I searched here to find the excact firmware but i didn't find it maybe there is not.I found an original firmware(as it says) close to mine from sammobile.com(there are more than one and it confused me al lot), flashed it and it came back to it's original form except for the boot logo which indicates me than it's not the original as i wanted. Anyway I didn't mind then because i was really tired from searching and i kept it. After months though, the battery starts draining like hell. It's at 67% when I turn on wifi and after 2 minutes screen starts flickering and all the sudden the phone turns off. I try to turn it back on but is shows 1% battery and of course it turns off. When I put it in charge after a while it shows again 67% or a little more. Anyway it turns off whenever it wants, when i play, when I talk to the phone, generaly whenever i need the battery. I tried another battery and it's about the same so i believe it's the phone, or the firmware i put I really don't know.
What I want to bring it back to it's excact original form if possible. Can I do that and if so can you tell me excactly what to download from the beginning??

Really appreciate your help!

MistahBungle said:

Get stock firmware from Samfirmware for country/carrier (doesn't matter which, but stay away from 4.0.4 if you intend to root the phone at any stage), boot into download mode, flash with Odin.

Am I going to give you a step by step for something as basic as this which has been covered literally thousands of times here over the past 2.5 yrs ? Absolutely not. Search; this info (guides) is easily found (Hint: stickied thread near top of Q&A has what you need).

Edit to add - If a clean install of stock doesn't help, given you've already tried another battery, replace the USB board/port. KeithRoss39 has a guide in the General section which has all the info you need to enable you to do this easily/quickly/cheaply.

Click to expand...

Click to collapse

Thank you for your time!
As I said I have spent many hours searching and changing, so of course I don't expect you to tell me how to flash with odin I already know that. What I wanted if possible was to give me the excact links to the files I have to download. From what you said it doesn't matter which firmware i get. I thought that was the most important so why the phone doesn't look like it came from factory? That's what I wanted. And the battery?? Ok I'll try to replace the USB port so it's not the phone. But I've already flashed that firmware and that came nowhere.

MistahBungle said:

Get stock firmware from Samfirmware for country/carrier (doesn't matter which, but stay away from 4.0.4 if you intend to root the phone at any stage), boot into download mode, flash with Odin.

Am I going to give you a step by step for something as basic as this which has been covered literally thousands of times here over the past 2.5 yrs ? Absolutely not. Search; this info (guides) is easily found (Hint: stickied thread near top of Q&A has what you need).

Edit to add - If a clean install of stock doesn't help, given you've already tried another battery, replace the USB board/port. KeithRoss39 has a guide in the General section which has all the info you need to enable you to do this easily/quickly/cheaply.

Click to expand...

Click to collapse

Thank you for your time!
As I said I have spent many hours searching and changing, so of course I don't expect you to tell me how to flash with odin I already know that. What I wanted if possible was to give me the excact links to the files I have to download. From what you said it doesn't matter which firmware i get. I thought that was the most important so why the phone doesn't look like it came from factory? That's what I wanted. And the battery?? Ok I'll try to replace the USB port so it's not the phone. But I've already flashed that firmware and that came nowhere.