There are 2 ways to stop applications that auto-start when you login to Windows Vista. You can either use the System Configuration Utility or the new Software Explorer in Windows Defender:
Method 1: System Configuration Utility
1. Click on the Start Button, enter msconfig and hit Enter.
2. Click on the Startup tab.
3. Uncheck items that you do want to auto-start and click OK.
Method 2: Windows Defender
1. Click on the Start Button, enter Windows Defender and hit Enter.
2. Click on the Tools from the top menu bar.
3. Click on Software Explorer and select Show for All Users.
4. Select an application to either Remove or Disable.