Microsoft changed a lot of things in Windows Vista (and, by extension, Windows 7). While most of your applications should work fine in Windows 7, you'll undoubtedly run into a number of apps that just won't work. And since you're going to have to move off of Windows XP at some point -- most likely before you're able to retire all your incompatible apps -- it's worth looking at some techniques you can use to run apps that aren't compatible with Windows 7 on the new operating system.
While most people look to application virtualization to run conflicting apps side by side or to run programs by "streaming" rather than "installing" them, many virtualization products can also be used to run older apps on newer operating systems. (For example, Symantec's Workspace Virtualization lets you run Internet Explorer 6 on Windows 7.)
Run your Windows XP apps in their own virtual machines
Another way to access Windows XP apps on a Windows 7 desktop is to run a full copy of Windows XP in a virtual machine (VM) on your Windows 7 host. Microsoft even provides a feature (based on Virtual PC) called Windows XP Mode, a free download for Windows 7 that gives you a VM for running your older apps. This is how Microsoft is able to claim Windows 7 has "100% compatibility" with Windows XP.
However, you don't need to deal with Windows XP Mode if you don't want to -- there's nothing stopping you from running Windows XP on VMware Workstation or another virtual desktop product.
Terminal Services or VDI published apps
An easy way to deal with incompatible apps might just be to run them on a different machine and access them from your Windows 7 host via a remote seamless window. You can do this with a Terminal Services or virtual desktop infrastructure (VDI) instance running your app with an icon in the start menu of your Windows 7 client.
Update your apps
Finally, don't forget that the simplest way to make an older app run on Windows 7 might just be to contact the vendor and get a new version of your app.
Will your apps be a problem in Windows 7?
The best way to figure out which applications will and won't work on Windows 7 is to just build a test machine and start installing your apps to find out. You can also get started with the Microsoft Application Compatibility Toolkit, a free download from Microsoft that contains components for automatically verifying and testing currently installed apps.
The bottom line is that Windows 7 is here to stay, and not all applications are going to be compatible with it. Fortunately, there are enough options out there that legacy application compatibility shouldn't be a problem for Windows 7 in your environment.
ABOUT THE AUTHOR
Brian Madden is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog, BrianMadden.com, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.