I don't know about every Windows installation, but my XP installed and defaulted to 60Hz refresh rate. This is the speed at which the stuff you see on your screen updates. The faster the better. 60Hz is pretty poor. Go on the web and find the driver for your monitor and install it. Then go in your display properties from the control panel. Goto SETTINGS -> ADVANCED -> MONITOR and check off the "hide modes that this monitor cannot display", then turn your refresh rate up to 85Hz or 100 or whatever you can. I run mine at 100Hz.

Caution: If no driver is available for your monitor don't go fooling with refresh rates unless you are sure your monitor can handle it. Doing so could damage your monitor. If there is no driver, consult the monitor manual or the manufacturer's website. They will usually say what Hz your monitor will work and at what resolutions.