Did you know that it's possible to run another operating system on top of your existing operating system? Indeed, it's possible to run another copy of Windows XP on top of your existing installation within a separate window.

This is useful for two key purposes. You could use your virtual operating system to test new software. If you install very similar software (security software is a good example) to your main system, you may find that they interfere with each other. It's been known for one security package to view a rival as spyware, for example.

If you want to try new security software, simply start your virtual operating system, install and then don't bother to save the changes you've made to your virtual operating system. Think of it as an ideal test-bed for using new software without it affecting your main computer.

A virtual operating system is also ideal for testing an operating system, such as a new version of Linux, when you're unsure about installing to your main computer.

VMware Player is a free solution that will enable to you host VMware virtual machines (operating systems) on your computer. The latest VMware Player 2 now supports USB 2, Windows Vista support and much more.

Note that you'll need to create your virtual machine within VMware Workstation or will need to obtain a virtual machine from another location, such as the preconfigured virtual appliances that VMware hosts online.