cant execute or unzip downloaded file

[tssamons]

I found the simcity 4 no cd format but once I download it my computer cannot acces the file. File is - dev-s4dll.rar
I cannot execute it or unzip it.???

The instructions prior to download simply say-

Install the game - Full Installation.

Replace the original SIMCITY 4.EXE executable with the one from the File Archive.

Play the Game!

I cannot find or access a new simcity 4.exe file after I download the file.

please help!