Microsoft on Monday pointed users to the first service pack for Windows 2000, an 87MB download that fixes an array of problems with the five-month-old operating system. Given the sometimes unreliable nature of Windows releases, many analyst houses, particularly the Gartner Group, had advised companies to hold off deploying Windows 2000 until Service Pack 1 was released. Nevertheless, Microsoft claimed last month that sales hit 3 million by the end of June. "Some customers who are more on the conservative side will possibly wait for a service pack, but all indications we had were that customers were not waiting," said Mark Perry, director of product marketing for Windows 2000 Server. The service pack is available for download at http://www.microsoft.com/windows2000/download/recommended/sp1/default.asp/ or on CDs available through Microsoft. Actually, Service Pack 1 has been available for download on other Web sites since Friday, Perry said, and more than 50,000 customers had downloaded it through Sunday morning. "Across our Premier [licensing] accounts for large enterprise customers within the Fortune 200 range - we have about 2,200 worldwide - what we've seen so far since the end of last week is that a little more than half have downloaded the service pack," Perry said. Service Pack 1 is focused on four areas, according to Perry: - Operating system reliability, including memory leaks and system hangs associated with third-party software; - Application and hardware compatibility, particularly installation problems associated with Windows 2000's signed driver technology; - Setup and installation problems; - Incorporating the several security updates that have been released since Windows 2000 officially debuted on Feb. 17. However, Service Pack 1 also caused new problems with Windows 2000. According to Paul Thurrott's Windows newsletter and www.wininfo.com Web page, the service pack "breaks" two firewall technologies: BlackICE from NetworkICE and ZoneAlarm from Zone Labs. Perry acknowledged the problems and said the ZoneAlarm problem was a connectivity issue. He said Microsoft was not sure if the ZoneAlarm and BlackICE issues were related. "We are looking at a short-term workaround or a permanent fix," Perry said. Microsoft has created two deployment options for Service Pack 1. Users can opt for the Express Installation, which targets Windows 2000 with specific updates and is about 13MB, according to Perry. The Network Installation, which Perry said companies preferred, can install and deploy both Windows 2000 and Service Pack 1 in one process, across the enterprise.