Rose - Dosbox won't affect anything on your computer.
It seems a bit overwhelming if you're not familiar with how DOS works but if you take it slow you can do it.
First off just download dosbox and then we can take you one step at a time on what to do. Click on the link InlandAZ gave you and download the one for windows - it will be the first one.
Oh Rose make sure when you save it you know where you saved it to so you can find it to install it. I generally save everything in My documents - just easier for me.