Windows 95/98/ME emulators
The Windows 9x series consisted of Windows 95, Windows 98, and Windows ME. Windows 3.x includes 3.0, 3.1, and 3.11. Playing older Windows games on a modern system can be difficult. There is no simple straightforward "emulator" for it, unlike DOS.
- Main article: Wine
Wine is for Linux, various BSDs, and OS X and allows Windows applications to run on those systems. Support for Windows 3.x and 9x programs is quite strong, though since it focuses more on modern games, they're the lowest priority.
- Main article: DOSBox
Windows 3.x, 95, and 98 can be installed in DOSBox. Windows ME can also be installed, but in comparison to the other versions of Windows listed here, it is unstable and runs very poorly in DOSBox. DOSBox was not designed to run Windows. Windows 3.x runs very smoothly, but 95 and 98 require more legwork (for instance, Windows 3.x will run games from a mounted CD drive just fine, while 9x require Daemon Tools to be installed inside the OS) and are much more clunky. They also run slower than unaccelerated QEMU. Running DOS games from inside Windows caused problems with a real copy. It is much worse inside DOSBox so do not run DOS games from Windows on DOSBox. There is no 3D acceleration available. Some games will not detect Windows properly and refuse to install. All the problems and bugs Windows had by itself will only be made worse using it in an emulator and without a real copy of DOS.
Step by step guide to installing Windows on DOSBox.
There has been interest in creating a spin off version of DOSBox that incorporates compatibility with Windows 95/98/ME called 9xbox, but as of now it has not passed the theoretical stage.
- Main article: PCem
PCem is an emulator for old x86 PCs that can emulate actual old hardware fairly accurately. Configuration is not the easiest, but once it's running, it works quite well. Needs somewhat powerful hardware to run.
Currently, it only emulates up to a Pentium processor on the latest stable release, but if you have the muscle for it, you can also emulate an S3 ViRGE, or even a 3dfx Voodoo.
86box is a fork of PCem and it has an extended compatibility compared to PCem, but it's harder to use.
Both of these emulators are good for general purpose x86 emulation. 3D acceleration isn't that great right now so it's better to use another option until 3D acceleration improves.
Windows can be installed through a virtual machine. 3D acceleration doesn't work very well however, and very few officially support the operating systems, leading to compatibility problems. The best free virtual machine program is VirtualBox at this time, which is cross-platform and developed by Oracle.
Some Win9x applications can be run on these systems. However, support is very poor. Selecting Windows 95 or Windows 98 in compatibility mode helps. 64-bit versions of Windows do not support any 16-bit Win3.x programs.  This limit can be passed using a program called Winevdm. Windows XP will get the best compatibility, however it is best to use it in a dual boot setup since it is unsupported and vulnerable.