How do I reinstall SP3 for Exchange 2010?

Hello,

I am having some Exchange 2010 issues and am wanting to reinstall SP3, but when I try, I get an error:

Some controls aren't valid:

Please select at least one server role to install.

All of the roles have been installed and I cannot even uninstall a role (greyed out)

I have version 14.3.132.002 of the SP.

Please advise.

Have a great day,

Don