Windows 8.1 file permissions.

Hi there to all.
Have this issue. I am an IT tech doing support for various clients.
One client pc is not happy, here is what is happening. Several weird scenarios is happenig. Yesterday, team viewer 12 started having errors. " your teamviewer account could not be activated... " researching that I found that it is the wintrust.dll is corrupt . recommended fix is to simply copy same file from another pc and replace. this leads into my real problem.

I can not copy and replace file. system permissions stops me. I checked and re-checked, No UAC restrictions, administatrator rights. checked folder permissions, checked file permissions, no block anywhere. then I tried changing the inherent permissions on the WOW64 folder where the wintrus.dll file is. File permissions wont allow me to change permissions

correct, folder permission wont let me create another user, neither everyone permissions. Never seen this is my life.

then i realized that the Pastel accounting problem that we were having for some time may be due to this. we have two other pc/s in the office that uses pastel that runs on the " permission issues" pc. one client pc will not find the pervasive license and has to be registered every time. Sure it is also a "file permission error"
Now, question is, how do i reset all permissions to default. is there a way to remove the apparent " invisible" block,
I did do all the obvious checks, firewall, anti-virus, rights, permissions, UAC,

Its weird that if I try to change the permission status anywhere, system reports that i dont have permission to do so

can you help????