I only know of 1 Dos emulator and I use it every day:
Dosbox. You should check their site and fora for help, but I can give you a quick start assuming you have an original cd.
1. Download Dosbox from
their site.
2. Install it and start it.
3. You have to pick which directory on your pc Dosbox should use as its C-drive (I usually install Dosbox in C:\Games\Dosbox and I create another folder called C in it. So Dosbox should use C:\Games\Dosbox\C as its drive C).
Everything in this directory is accessible by Dosbox.
4. Tell Dosbox which folder to use as C-drive by using mount. Using my example I type: mount c C:\Games\Dosbox\C
5. Tell Dosbox which directory to use a CD-Rom drive. If your CD-Rom drive is D, than type: mount d D:\ -t cdrom
6. Now you can access the C-drive by typing C:\ and your CD-Rom drive as D
7. Install the game as usual
8. Play the game as usual
Extra tip: Open the dosbox.conf file in your Dosbox-directory and add the following lines to the end of the file so you won't have to typ it everytime you start dosbox
mount c C:\Games\Dosbox\C
mount d D:\ -t cdrom
C:\
Offcourse, you can add more drives with the same command and you can assign any letter except the z. Again; Dosbox can only access those directories which you've mounted. To keep thing save, dont mount your entire C-drive by typing: mount c C:\
Hope this will get you started.