To restore a single user's Mailbox or folder is currently only possible in VPOP3 Enterprise, and requires a second PC to act as a temporary VPOP3 server.

You need to:

• Restore your latest VPOP3 backup to another PC (a temporary VPOP3 server)
• Configure your email client to access the temporary VPOP3 server using IMAP4, as well as your normal VPOP3 server
• Use your email client to copy the messages from the relevant IMAP4 folder(s) on the temporary VPOP3 server to the normal VPOP3 server