Dos lagging

My computer is running fine, and I don't see any lag. But when I open a dos game, my computer lags the hell out of it, making it unplayable. 
Why is my computer lagging the dos games?

Are you using an emulator or are you just running the game? If you use an emulator try without one and if you play without an emulator try playing with one.

The latter, do you know any good emulators?

Dosbox is the best one I've come across although it may be a pain to setup for the first time.

ok downloaded... but I have no clue how to use it. 

log into MSN.

Well I am telling this from memory so...

Open the program, and depending on where your game is (I assume it's in C:/ ) type "MOUNT C: C:/" and the emulator will allow you to access the drive. Open the game folder with the emulator (e.g. "cd GAMES" ) and you will open the C:/GAMES folder. You can type "dir /p" to view all the folders and objects within one map. Once you find your game all you need to do is type "Start.exe" or whatever the executables name is to run it. You might want to adjust the CPU usage and frameskip with F1-F12.

ok