Windows Vista can already run most XP applications, with no need for any additional software.
They are "compatible" in the sense that many applications that run on Windows XP will run on Windows Vista.
Many applications and games written for or compatible with Windows 98 will run on Windows Vista.
Yes ofcourse, Windows Vista is upgraded version of Windows XP. Obviously it can run Windows XP applications.
your computer might not be powerful enough to run vista. but to be honest i hate vista, get windows 7. Are there any applications running?
Go no less than 1gb for vista.
Yes. Windows Vista can run many games and applications that are available for download. You may wish to check to see if there are any known compatibility problems between your game and Windows Vista.
Windows 8 does have the ability to launch applications in compatibility modes which support older Windows versions.
Most applications written for XP will work perfectly fine on Windows Vista. The ones that don't usually either rely on an obsolete library, or require administrative privileges to run, which Vista no longer grants by default.
Most DOS applications don't run well in Windows Vista, although CLI and text-mode programs like Lotus 1-2-3 should run ok. 64-bit versions of Vista cannot run DOS applications at all. If you want to run Lotus 1-2-3 on those, try using a program like DOSBox.
In what sense? They are both operating systems. If you're asking if applications written for Windows 98 will run under Vista, I would have to say yes. At a minimum, they can be run in Compatibility Mode.
Windows Vista
Only Windows 64-bit operating systems can run 64-bit applications