Download a preset you like, put it in the SweetFX folder created where the bf4.exe file was.
Delete the SweetFX_settings.txt file and replace it with the new file. Rename the new file to SweetFX_settings.txt and ...
Voila! Now just normally open bf4 from origin or shortcut and use scroll lock to toggle reshade on and off.
The administrator has disabled public write access.