We have a lot of threads asking about running Doom on Windows XP/Windows Vista/Windows 7.
Please do not create new threads about this, as it is something which has been asked a thousand times already. New threads about this will be deleted. Read below for some help and tips.
Windows 2000, XP, Vista, and 7 have limited DOS support, so doom(2).exe will not work properly if you are using these operating systems. Disabling sound effects and/or music may solve the problem. DOSBox should work fine if the system is newer (as it requires considerable processing power).
Final Doom and Doom: Collectors Edition come with Doom95 which was an official port of Doom to Windows made by Microsoft. However, you may still have problems with this, as the port has bugs in places. This includes problems with the mouse and possibly the graphics.
To play under Windows 2000, XP, Vista, or 7, we recommend a third party Doom source port as a convenient option.
The Steam versions of the Doom games run inside DOSBox. If you want to enjoy one of the many source ports that run the games, or DOSBox isn't working for you, navigate to C:\Program Files\Steam\steamapps\common (or your version thereof) and extract the WAD files from the game directories. Then place them in their own folder somewhere and watch the Youtube video below.
Here are some step by step instructions for those who need them. NOTE THAT I AM DOING THE INSTRUCTIONS FOR DOOM 2, BUT IT WORKS FOR DOOM 1 OR FINAL DOOM AS WELL:
Install the game. The installer is pretty self explanatory. When you are done you should have the game installed in c:\doom2 or whatever.
Disregard doom2.exe and Doom95; they don't work right under newer Windowses.
Download a "source port" and unzip it into the directory the game is in. For instance if you want to get ZDoom, which is always a good first choice, go to the ZDoom website linked above and download one of the versions and then unzip the zip / cab into c:\doom2 or whatever. I think XP has unzipping built in but for whatever reason you can't unzip files, Google for "WinZip".
Once you've unzipped, say, ZDoom, in the c:\doom2 directory, double-click on "ZDoom" or "zdoom.exe" in order to launch ZDoom. Then screw around with the options and play Doom!
Additionally, in order to use custom WADs, unzip them into c:\doom2 as well and then either drag the wad file onto the ZDoom executable in order to launch it, or hit Windows key + R to open the run menu and type in "c:\doom2\zdoom.exe -file wadname.wad" to kick it old school.
Edited by myk July 12, 2008: Fixed some facts, added some links, updated some info, and corrected order for clarity.
Options for running Doom engine games on 2000/XP-computers without ports
1) Run the game with DOSbox. If the game feels sluggish, open the DOSbox config-file, set the "cycles"-setting to 7000 & reduce the screen size/detail in game.
2) Set up Bochs with Windows 9x or FreeDOS. Takes time & effort.
3) Set up your computer for a dual-boot using your current operating system and Windows 9x. Takes time & effort.