One has to be careful with dll files in case they are shared. try renaming it first ProgramName.
dll old-- and run your system awhile to see if you get any warnings first, especially at boot up. Then when no problems appear or crashes show up in Reliability History(in the Action Center) then you can unregister the dll.
Open an Admin command prompt by right clicking the windows icon and choose it.
For the path name you can use drag and drop in windows 8 by opening file explorer and dragging the dll to the command prompt after you type regsvr32 /u"
example: regsvr32 /u "C:\Windows\System32\amdmantle64.dll"(this is for an AMD ´graphics dll)
Don't forget quotes
Register dll file
To register a dll or ocx file, open a command prompt windows as an administrator, type the following and hit Enter:
regsvr32 “path & filename of dll or ocx“Unregister dll file
To un-register a dll or ocx file, open a command prompt windows as an administrator, type the following and hit Enter:
regsvr32 /u “path & filename of dll or ocx“This will register or unregister the dll file.