Removing OpManager 6.0

HI,

I installed OpManager 6.0 on my windows 2003 enterprise machine and then uninstalled it. Now when I install 5.6, it installs successfully but at the end error come �Unable to start OpManager as a service� . In services Manage OpManager service is in automatic and started state. When I try to run OpManager client, it says �check if server is running�. I believe that version 6 is not uninstalled completely and it has still occupied the system, because when I again tried to install 6 it installed and worked properly. Please let me know how can I remove OpManager completely and install 5.6 again.

Thanks & Regards