Who would want to upgrade from Windows XP to Windows Vista just to realize that some mission critical software aren't working anymore. It could be expensive software like AutoCAD 2007, 3DS Max 9, Adobe Photoshop CS2 or the smaller ones like Norton Antivirus, Nero, ZoneAlarm Firewall, Picasa, Tally or even iTunes.
While the best approach would be to directly talk with the software vendors, that may not be always possible. So here a couple of options to help you find what software works and what doesn't work with Windows Vista.
How to make sure that your software and games will work with Windows Vista
Using VMWare Virtual Machine
Get the free trial DVD of Windows Vista and install that as a guest OS using VMWare Workstation 6.0 on your Windows XP computer. Now install the software titles on this Vista Virtual Machine without affecting your existing XP setup. Alternatively, if you have a spare computer, install Vista directly bypassing the VMWare route.
Using Windows Vista Upgrade Advisor
Microsoft released a new version of Windows Vista Advisor software today. Run this program on your XP computer and it will prepare a software compatibility report with a list of programs that might exhibit problems after the upgrade to Vista. Here's a sample report we got:
Sonic DLA - This program must be uninstalled before upgrading to Windows Vista. After upgrading, you can try reinstalling the program.
Sonic MyDVD LE - This program might have minor compatibility issues after upgrading to Windows Vista.
Dell Inc. Utilities - Go to the manufacturer's website to download the latest utilities for your system.
The Upgrade Advisor gives fairly decent recommendations and also points to the manufacturer's website where a new version of the software might be available. Highly recommended.
Using Windows Application Compatibility Toolkit
Microsoft will soon ship a free toolkit (discussed here) that will tell you which installed software will not work with Windows Vista in place. This program is currently available only for beta testers.
The MSDN website also says that all existing Win32 and .NET applications will continue to run under Windows Vista without modification. The same holds true for MS-DOS applications.
The good news is that there does exist a simple workaround to run legacy software in Windows Vista - right click on any app and choose the Compatibility Mode just like you can do inside XP.
Sooner or later, most vendors would definitely make their software compatible with Vista - the question is whether they'll ship a free patch / service pack or release a paid upgrade.