How To Change The Drive Letter For DVD P

How Do I change my drive letter on my dvd cd rom and cd-rw because before I install the cd-rw drive the dvd cd rom drive letter was (E) now its (F) and everything for games that I install from the drive letter (E) is not working on the cd rom drivethe games only work if I put them in my cd-rw drive so my best beat is to change the drive letter back to the way it was before to get my cd rom games working on my cd rom drive not the cd-rw drive.I’m running windows 98(se) I remember doing it oncebut forgot how again to change the drive letter I think start and run and type in something.