Many operating systems have their own utilities to carry out tests on the operation of various areas of information, the Scandisk and Defrag utilities in both DOS and Windows 95/98/98SE/ME for example. Some operating systems have help on troubleshooting, such as the Help and Support Centre in Windows 98/98SE/ME/2000. Some operating systems have monitoring tools such as the Performance Monitor in Windows NT/2000. Although these tools do not run diagnostic routines, they do monitor how the various parts of a system are working and can be useful when troubleshooting or finding out why a machine is running slowly.