Help to upgrade to windows 7

I have a dell laptop with vista home. I am trying to upgrade to windows 7 but can't. after install starts it shows that it is gathering information. after a bout an hour i get this message

The following issues are preventing Windows from upgrading. Cancel the upgrade, complete each task, and then restart the upgrade to continue.

• 
  [*]Windows needs to be restarted so necessary changes to system files can be made before continuing.
  
  

Upgrading Windows will affect the following devices and/or programs:

• These programs might not work properly after the upgrade. We recommend uninstalling these programs before upgrading. Cancel the upgrade, open Control Panel, and search for "uninstall a program". (Note: Programs marked as * can be safely reinstalled after the upgrade.)

• • 
    [*]Remote Access Application
    [*]Dell Modem Diagnostic Tool

An upgrade is always a mess. Save your data and make a clean install.

Clean Install with a Upgrade Windows 7 Version - Windows 7 Forums