How to register a DLL file in Windows 10

To register a dll, you open a command box as admin and then use regsvr32 /i <dll_name>.

Tha said, your problem seems to be that you just can't copy the file. Again, open a command box as admin and do the following:

1. ren c:\windows\system32\filename.dll c:\windows\system32\filename.old
2. copy c:\randomlocation\filename.dll c:\windows\system32\filename.dll

If the file is in use, you should do this in safe mode, command prompt only. If you hose your system, you can delete the dll you copied, and rename the .old back to .dll.

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1. Copy .dll or .ocx to c:\windows\system32
2. Type cmd in Run menu, it will search cmd.exe, right click and click Run as Administrator
3. It will show a prompt at c:\windows\system32
4. Type regsvr32 ocxname.ocx to register .ocx
   or
   type regsvr32 dllname.dll to register .dll