The update for KB2758857 made a change to the kernel32.dll file.
Therefore you need to check which version of the file you have running on your system. You can do that as follows :
Use Windows Explorer to navigate to the C:\Windows\System32 folder. There you will find the kernel32.dll file.
Right click on the file and select Properties. From the Properties display, click the Version tab. The first piece of
data displayed on the Version tab is the file version. If the version is 5.1.2600.6293 then that is the level of the
file that was shipped with KB275887.
You should also check the same dll (kernel32.dll) in folder C:\Windows\System32\dllcache as there is a copy in
there as well.
If you do NOT have the fix applied, it is likely the file version shown will be 5.1.2600.5781
If I needed to revert back to the previous dll, I would do the following :
Rename the kernel32.dll file on both of those folders to Okernel32.dll
Copy the version of kernel32.dll from folder C:\Windows\$NTUninstallKB2758857$ to C:\Windows\system32 and C:\Windows\system32\dllcache.
Reboot.
Whenever I do ANY changes like that I have always taken a backup of my system before I start.
