I mentioned this in my post in regards to iTunes and my frustrations that I was glad I installed it in a SVS layer instead of installing directily to my computer.
Let me explain some more in regards to the beauty of this great product. (BTW I am an Altiris Engineer for ITS Communications the Platinum Partner of the Year for Altiris so just wanted to disclose everything.) Altiris has release Software Virtulization Services (SVS) for free personal use (see http://juice.altiris.com) so go ahead download it, and come back and read this blog.
SVS does something different then VMWare, Xen, and Virtual Server, which all virtualize the entire OS (Operating System), SVS works on the application level. Instead of actually installing the application, with SVS you install into a virtual file system which can help prevent DLL hell when you have different version of a program installed or conflicting applications. For example w/ SVS you can run IE6 and IE7 at the same time. Do you need Word 97 for a certain Macro and need Word 2003 for the rest of your day to life? Then install Word 97 into a new SVS layer and only activate word when you need to use it.
The beauty of SVS is that everything done in the SVS layer only affects that layer. A great example is Firefox which always updates itself. Need to maintain a certain version of FF? Everytime FF downloads an update, just reset it and you back to the orginal version.
I can’t sing the praises of SVS enough, I install all of my software in SVS layers, including Windows Live Writer which I’m using to blog this. When the beta ends, I just delete the SVS layer and I’m all set. No hidden remains of Windows Live Writer.