Take the back of C:\Program Files\Urchin and sitedata folders.
Double-click on the urchin5xxx_win_setup.exe file and follow the instructions in the Welcome and License Agreement dialog screens.
In the dialog screen labeled Preparing to Upgrade Urchin Installation, the installer will present you with a list showing you the directory location and web server port number it has determined for your existing installation. It will use these parameters for your upgrade.
Click the Next button and the installer will proceed with converting your installation to the new version. Your report and configuration data will automatically be preserved during this process.
Go to the registry and edit the value of HKEY_LOCAL_MACHINE\SOFTWARE\Ensim\WEBppliance\Addons\UrchinAddon\UrchinName key and set it to Urchin 5.0
(Step 6 only ensures that in the CP Urchin is displayed as "Urchin 5.0")