Hi there and welcome here at RD
to better diagnose your problem first of all please put here more info:
* PC hw configuration (in particular video card and its driver)
* Operating system
* Antivirus / Firewall
* do you downloaded rF or bought its DVD ?
* how repeat the problem and its error message, if any (add a screenshot)
when you say 5h to install what do you mean ?
did it frozen for a while or it simply asked a bit more than other program ?
I'm sure someone will help you to sort it out
ciao