Click the Preferences button on the toolbar.
Choose Preferences... from the Virex 7.x menu.
In the Scan dialog, select the location that you want to scan. Choose from:
Home
Documents
Desktop
Public
Applications
Macintosh HD
All Local Volumes
Choose...
Click the Scan & Clean button.
A status bar shows while Virex examines the selected item, and cleans infected files. The results appear in the Results area.
To stop the scan, click the Stop button in the upper-right corner.
Quick method
Select one or more items in a Finder window or on the Macintosh desktop.
Drag the item(s) onto the Scan & Clean button or the Virex application icon.
Items that can be dragged include documents, files, folders or volumes. You can also scan files by dragging them on to the Dock icon.
This information and more can be found at http://virexhelp.com