[PC]Battlefield 3 Stuck at Connecting (Black "Loading" Screen)

Some of this you did but try all of this please...

Run the game as Administrator:
Go to the Origin games folder (C:\Program Files (x86)\Origin Games\Battlefield 3) and find Bf3.exe. Right click it and go to PROPERTIES, then COMPATIBILITY and check the box next to RUN THIS PROGRAM AS ADMINISTRATOR.

Run Origin as Administrator:
Go to C:\Program Files (x86)\Origin and right click on Origin.exe and go to properties. Then go to compatibility tab and check the box next to RUN AS ADMIN.

Disable Origin in game:
In Origin - Application settings - Origin in Game - disable Origin in game

Origin Cloud Storage turn it off
Origin, settings, General

Reboot PC then test BF3

Yep tried all with no luck
I'm going to reinstall my network drivers, since restarting the router did nothing either, and I'll check back.
It's kinda odd that I can play BF4 just fine but not BF3, I've also played Titanfall recently, the only game giving me problems with connections is bf3

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Reinstalling my network driver did not help either. I have no idea of what to do!

I can also play coop with a friend, only mp isnt working!

Try this / update all this...

Latest version of DirectX see this page
http://www.microsoft.com/en-ca/download/confirmation.aspx?id=35

Reinstall Microsoft C++
NOTE>>> you need to select the x64 or the x86 file depending on what architecture your computer has. To find this out, Click Start, right click on "Computer" and select "Properties". Under system type is should say "32-Bit Operating System" or "64-bit Operating System". If 32-bit operating system, download the x86 file, and if 64-bit download the x64 file.
http://www.microsoft.com/en-US/download/details.aspx?id=40784

Update your Microsoft .NET framework.
http://www.microsoft.com/en-ca/download/details.aspx?id=30653

Adobe Flash Player update
http://get.adobe.com/flashplayer/

Go to Punk Buster site
http://www.punkbuster.com/index.php?page=pbsetup.php

1- Download PB then extract files to your desktop.
2- Open Punk Buster folder.
3- Click on the PB setup and it will open.
4-Add your BF3 game to punk buster its at the top of Punk Buster.
5-Then update punk buster again at the top of Punk Buster.

Reboot PC test BF3

All of these are already installed/updated, I reinstalled everything just to be sure aswell.

I've managed to get into a round, but when I got out and tried to connect to another server it did the same, trying to connet to the same server I was previously didn't work either. I honestly have no idea of what could be doing this

Try this......

Another thing that may be worth trying: run a Clean Boot: http://help.ea.com/en/article/how-to-clean-boot-your-pc/
This should ensure that no programs are interfering in the background.

Check your firewall to be sure it is open to the game and not blocking it.

 See programs below known to make issue...

Disable Mantle if you have it and try Direct X, Turn OFF Anti-Aliasing Deferred in video card settings in game. If you have page file turned off then turn it back on as this can make errors even with 32gigs ram.

Others have said if they uninstall MSI Afterburner issues / crashing is stopped. So if you have this installed remove program and test BF4. Also look at other programs as Asus Game First Service, Razer synapse, Razer Cortex, Qualcomm Killer Service , Fraps, EVGA Precision, Geforce experience, be sure to turn off the streaming function that is enabled by default ,Raptr, RivaTuner , ASRock eXtreme Tuner, Steam, Skype, aero ,Overwolf extra program in teamspeak and xfire are known to make issues as well. And I am sure more programs not in my list yet turn one off at a time and test BF. 

On my Firewall all ports/connections are open to the game
Clean boot didn't help
I don't have mantle, anti aa is off and pagefile is manages by windows.

I don't understand how the game started fine once and then doesnt work again!

I do have Synapse and Qualcomm but if I unnistal these I can't play anyway, because I loose my mouse and headset and internet connection

I don't think theres a solution to this

If the clean boot did not change anything then it is not a program so  no need to remove them.

When you reinstalled BF3 did you remove the BF3 folder in my documents? If no try this...

Don't give up we just have to find the correct fix for you and sadly it does not always come fast.

Try this please.... 

C:\Users\your PC Name\Documents\Battlefield 3
BF3 folder in my documents holds game configs and screen shots even if BF3 is installed on different drive. When you uninstall BF3 it does NOT remove this folder. So when you install the game again you can still have the same issues. Even if its not a new install it is still worth trying as the game cfg could be mucked up.

1- Go to my Documents and remove BF3 folder place it on your Desktop or trash.
2- Be warned you do have to set up your in game settings again.
3-Repair BF3
4- When done go test your game. If it fails reboot your PC and run repair game again and test BF3.