Hello Jay,
To make sure that you will not lose any previous settings of your system you could create a backup first and then proceed with installing our controls. For more information you can take a look at
this How-to article. For the second question, unfortunately you can not download and install only a single Telerik control. In order to test the RadMenu you will need to download and install the whole package. You can find the latest version
here.
Best wishes,
Kate
the Telerik team