If you already have Firefox 2.0.0.1 installed and the Sunrise XP extension is grayed out, you need to do the following to properly update it to the latest version.
- Uninstall Sunrise XP using "Control Panel -> Add Remove Programs"
- Close and restart Firefox. This ensures that Firefox sees that the Sunrise XP and the browser extension has been uninstalled.
- Reinstall Sunrise XP 2.03a.
- Close and restart Firefox again. Verify that the Sunrise XP extension is present by selecting "Tools -> Add-ons" from the main menu.