TweakUI is a software utility that lets Windows 9x, Windows NT, and Windows 2000 users modify the desktop user interface and other system characteristics to their liking. Using TweakUI, you can change the menu speed, how windows are animated, and a number of features about Microsoft Internet Explorer. TweakUI allows the user to change settings that are not easy to locate, including some in the system registry. For example, a user can speed up system startup by reducing the frequency with which the ScanDisk utility is run.
Microsoft includes TweakUI as one of several "Power Toys" that can be optionally installed. Users are advised to always back up their registry (for example, copy it to a new file with another name) before doing anything that might modify it.