The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the WinVNC.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.
The process known as VNC server for Win32 or TightVNC Win32 Server or VNC Server for Win32 or VNC server for (version X64/win32) or VNC server for win32 or NA server for Win32 or NetworkStreaming Customer or VNC 3.3.7
belongs to software UltraVNC or TightVNC or RealVNC Ltd. - WinVNC or TightVNC Win32 Server or AT&T Research Labs Cambridge - WinVNC or Tridia Corporation WinVNC or Ultravnc or VNC or VNC Server
by UltraVNC (www.uvnc.com) or Constantin Kaplinsky (www.tightvnc.com) or RealVNC (www.realvnc.com) or AT&T Research Labs Cambridge (www.att.com) or TightVNC Group or Tridia or Network-anywhere or UltraVnc (www.uvnc.com).
Description: WinVNC.exe is not essential for Windows and will often cause problems. The file WinVNC.exe is located in a subfolder of "C:\Program Files" or sometimes in a subfolder of "C:\Documents and Settings" (generally C:\Program Files\RealVNC\WinVNC\ or C:\Program Files\ORL\VNC\).
Known file sizes on Windows 8/7/XP are 712,704 bytes (19% of all occurrences), 474,624 bytes and 44 more variants.
It is not a Windows core file. The application listens for or sends data on open ports to a LAN or the Internet. You can uninstall this program in the Control Panel. The program has no visible window. WinVNC.exe is able to record keyboard and mouse inputs, hide itself and monitor applications. Therefore the technical security rating is 40% dangerous; however you should also read the user reviews.
In case you experience problems using WinVNC.exe, you can uninstall the associated program (Start > Control Panel > Add/Remove programs > UltraVNC or TightVNC), look for help  from the software company Ultravnc or update  to a possibly bug-fixed version.
Recommended: Identify WinVNC.exe related errors
External information from Paul Collins:
Important: Some malware camouflages itself as WinVNC.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the WinVNC.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.
A clean and tidy computer is the key requirement for avoiding problems with WinVNC. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.
Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off doing a repair of your installation, or in the case of Windows 8, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.
To help you analyze the WinVNC.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.