Steinberg's Virtual Studio Technology provides a platform that allows developers to create virtual musical instruments and audio effect plug-ins for use in digital audio production. VST plug-ins cannot run on their own: to use a VST instrument or effect, open it in a digital audio production workstation like Cockos Reaper. To enable a newly installed VST in Reaper, direct the program to the folder on your hard drive that contains the VST, then scan the directory for the new VST.
Open Reaper. Click "Options" in the top menu bar, then select "Preferences" from the menu that opens.
Click the "VST" link under the "Plug-ins" heading. Click the "Add" button in the top right-hand corner of the "Reaper Preferences" window.
Navigate to the folder containing the new VST plug-in. Click on it, then click "Open."
Click the "Re-Scan" button. Reaper scans the directory for new VST plug-ins and adds them to its list of VSTs. Click "OK" when the scan completes.
Click "Insert" in the top menu bar, then click "Insert Virtual Instrument on New Track." Click "VST" in the left-hand column, then click on the new VST. Click "OK" to add it to a new track in Reaper.
If you can't find a newly installed VST, check "Program Files\VSTPlugins" and "Program Files\Steinberg\VSTPlugins." Most VST installers use one of these two directories as the default location.