I noticed that 10.1 was release to everyone now, so I downloaded and tried to install, but it told "Orion Network Performance Monitor is already installed. To repair this installation, use the Add or Remove Programs control panel".
So I just wanted to make sure, if I installed 10.1 RC4, I don't need to do any updates, is that right?
Correct. If you installed RC4 you have the final bits.