Report
Here is the low-down from Microsoft: 'Windows Vista Upgrade Advisor is designed to help Windows XP users identify whether their PCs are ready for an upgrade to Windows Vista, which edition of Windows Vista meets their needs, and which features of Windows Vista will be able to run on their PCs. Download the Upgrade Advisor to run an analysis of your current PC and use the detailed feedback to ensure that your PC is ready for the edition of Windows Vista that you want'.

We do find it a bit strange that they didn't release a version for Windows 2000, Me or 98. Surely, people using these systems are most likely to update to Windows Vista.