You do not need to uninstall CS4, and would not recommend you do so.
Bridge CS4 is probably running in background as you have the option to start at login checked in advanced prefernces. Uncheck this.
Or open Task Manager and click on processes tab, and close any bridge CS4.exe.
Only one bridge can run at one time.
You can also look in the Windows System Tray for the Bridge CS4 icon and right-click on it. If "Start Bridge at Login" is checked in the menu that shows up, uncheck it to stop Bridge CS4 from starting when you log into Windows, then click on "Exit Bridge."
You can then start Bridge CS5 and launch Camera Raw.