RAR file? I'm stupid and need help, please!

[Czerny]

I'm obviously a real beginner at this. But I bought the Hitman 2 PC game and am trying to get it going. It keeps asking for the CD even though I have the original in the drive.

I downloaded the patches, but don't know what I am doing.

It says to : "Replace the original HITMAN2.EXE executable with the one from the Executable Archive."

The file I downloaded was a RAR file. How do I extract it or whatever I'm supposed to do. How do I "replace" the file?

Thanks for any help you can give!