2000 Professional is relatively stable. It is less of a hog than Windows XP (although you can alter XP settings to optimize it for your particular PC).It has the simple look of Windows 98, but it does not crash as often. 2000 is based on NT technology, a precursor of XP (unlikeWindows 2000 Professional will receive security patches until 2010. So if you buy it now, it will be officially secure until 2010.You must take a few steps when installing this OS.1. Download all windows updates.2. Firewall. Zone Alarm's free firewall works well3. Antivirus -- antivirus software is mandatory, try symantec corporate edition.