NVRefreshTool is a utility used to fix the problem in Windows 2000/XP that sets your refresh rate to 60Hz when you play ANY game. This problem occurs whether or not you have a higher refresh rate set in your Display Properties of Windows.

NVRefreshTool is simple and easy to use. Just load up the NVRefreshTool program and it will automatically detect the maximum refresh rate at each resolution that your monitor supports. If you're an advanced user, you can customize each refresh rate at each resolution.

From the author:
Quite a few new features in this version--Most importantly 41.xx driver support, the addition of Horizontal and Vertical spanning support(there are some limitations to this), updated the installer, packed the nvrt.exe to use a smaller size, updated the help file with some new information(such as Battlefield 1942 refresh rate problems), a few coding updates, and a number of slight UI changes that just seemed as eyesores to us now.