It is a problem with Windows, not a bf4 problem. I had this and no amount of trying fixed it, I would have to restart my machine EVERY time I wanted to play a new game. REALLY frustrating.
I even tried uninstalling & reinstalling the game, removing the plugin, using third party tools to end the process, and using command line (as admin) "taskkill /im bf4.exe /f"
Nothing worked. NOTHING. Even process hacker failed me.
It turns out it is not a bf4 problem, but a windows problem. Something has become corrupt. Even Microsoft can't help - look at some of the comments on that page, people are having the SAME access is denied errors with skype, spotify etc.
The only way I could fix it was to perform a "system restore" to a time when it worked (Google will help if you don't know how). In the end it was relatively painless to do & much easier & faster than downloading again & reinstalling. Just do it, just fix your machine.
If bf.exe can not be closed in Windows 8 and 8.1 You should close Windows with command "shutdown.exe /s /t 0".
Otherwise the bf.exe will be "hanging" in the TaskManagers "details"-tab (even after normal shutdown).
This has something to do with Windows 8 hybrid shutdown that enables computer for faster reboot time... go figure...seems to be a nice feature ;-)
Anyway this kind of "special" reboot fixed my issues with BF4 and hanging bf.exe.
Hope that helps.
ps. Command can be found under C:\Windows\System32\ -folder
