I am running XP Pro, which works fine with me, but I also set up a Virtual Machine with XP also. In this VM window, I installed all the different browsers to make comparisons and testing of web pages - how they are seen on the different browsers.
I also use this VM window to test third party software, and general web browsing. If I did hit something abnormal or suspicious, no problem, would just copy the VM window folder/files over itself and cleans from the problem.
My VM disk is 10.26 GB, small enough to store on my USB drive as well.
Think of the VM window as a containment field. It is a barrier between your base computer setup and the Virtual computer setup. The disk in VMware is a virtual disk, and shows up in the base computer as a file. As far as I know, and others, please speak up if I got this wrong, that any malicious software running in a virtual machine will not affect the base computer system.
VMware player is a free download. (requires a free registration to download)
To set up your containment system:
1. Download and install VMware player.
2. Create 'New Virtual Machine' and install your OS into it.
3. Install Firefox 9or/and other browser software. You can also install AVG anti virus software
4. Do all your browser customizations.
5. Copy the VM folder to another location, this will be your baseline and restore point
If there is a virus or malware lurking in your VM window, then close VMware, delete the folder, and copy the baseline where the folder used to reside. Start again.
This method will save you lots of hassles. A must to try out third party software. It is also the easiest way to break into Linux - I have Ubuntu 10.04 in a VM window. You can use VMware for windows 95/98/NT/2K/XP/Win7 as well.
Use DOSBOX for Windows 3.1. Believe it or not, there was a need to run Windows 3.1 to run some legacy software to extract data (engineering thing), and DOSBOX does this well, where it is problematic and not supported with VMware.
In using VMware, make sure you download the tools/utilities for each OS system. This will allow the screen resolution to change on the fly as you re-size the VMware window.
There are plenty of resources here on the Island that can help you with questions.
VMware Player Download Link: http://www.vmware.com/products/player/