Yes, AnswerWorks English Runtime 5.0 is a replacement for AnswerWorks English Runtime 4.0. It has all features of AnswerWorks English Runtime 4.0. I suggest you uninstall the old application using the Add or Remove Programs option:
If you use Windows XP or bellow, you can go to Start > Control Panel > Add or Remove Programs. In the Currently installed programs box, click on the program and then click Remove.
If you have Windows Vista or above, you need to go to Start > Control Panel > Programs > Programs and Features. Select the application and click on Uninstall.