1. Easiest way is to use something like VMware, which can let multiple operating systems run on one machine - they all think the machine has their operating system on it as all they are doing is talking to the VMware interface

   There is apparantly a free version that can be downloaded on the web

2. SOURCE - We use it at work.
3. The Wine emulator will get you partway there, althought it mostly only emulates Windows windowed applications. It does have partial support for DirectX games, but is somewhat limited.

   I believe there is a project for a fully-compatible DirectX 9 emulator for Linux, but I cannot remember who…when it comes back to me, I'll post it.

   Also, if you want to run .NET applications, you can install Mono.

4. It is impossible to do that

Tags: understanding linux kernel, linux file system