Comdlg32.ocx problem

my computer never came with Comdlg32.ocx and i need it to use any of the f7 repaints that were from railsimulator such as the NP or GN repaints. i tryed to download it and following the instructions given to me from the windows website i tryed to install it. the computer would let me put it into the correct place but when i tryed to install the repaints i kept getting the error that the file Comdlg32.ocx is missing. i am running on windows 7. any help out there?