The Department for Work and Pensions is pressing ahead with plans for one of the world's biggest upgrades from Windows 2000 to XP, although a test in November went disastrously wrong.
The upgrade of 128,000 machines is scheduled to go ahead between February and June 2005.
The department initially told Computer Weekly that the project was on hold after a pilot involving 30 PCs brought down 40,000 machines last month. A spokeswoman subsequently said the upgrade would go ahead subject to the results of an "impact analysis" of the crash.
The DWP is upgrading to Windows XP because its multibillion-pound IT-based modernisation strategy requires that where possible it buys packaged software rather than bespoke systems.
The packages it wants to buy require the department to run XP. The newer operating system also offers better security and stability, the DWP said.
The upgrade will only go ahead if the department is assured by EDS, which leads the Affinity consortium running most of the department's IT systems, that there will be no repeat of the crash. A DWP spokeswoman said the impact analysis by the supplier would gauge whether "we are secure to carry on with the upgrade and make sure we preserve business continuity.
"If our suppliers found something that gave us cause for concern we would reassess the position and if necessary reassess the timing of roll-out, but we are not expecting that to happen."
November's crash happened in part because of the power of remote upgrade tools which allow technicians to modify tens of thousands of machines using simple routines at a single terminal. It is believed that an EDS operator allowed Windows XP to be installed on 40,000 computers instead of the 30 in the trial.
A configuration issue between Windows 2000 and XP caused the machines to crash on Monday 22 November and it was not until Friday of that week that all systems were fully functioning.
Procedures have been strength-ened to ensure that a single operator cannot perform a remote upgrade accidentally, EDS said.
Some of the DWP's welfare systems run in part on Fujitsu mainframes that date back more than a decade. In its strategy documents, the DWP said all of its equipment could not be feasibly replaced with fully integrated systems in the short term.
The DWP is the largest employer in central government and spends £1bn a year on IT systems and services. EDS runs most of the IT services and systems for the department under an "Accord" which was awarded under the private finance initiative. Contracts awarded to EDS under Accord have a total value of £4.5bn representing 85% of DWP business by value.
But since Accord was signed in 1999 the DWP has decided to move away from PFI under the umbrella of a series of framework arrangements called "Unity." It said it is reducing the proportion of business with EDS and has let contracts to IBM, Accenture, Fujitsu, Booz Allen Hamilton, and Xansa.
No need to rush XP upgrade
Many corporate users are not rushing to upgrade from Windows 2000 to XP as support for the older operating system is available until September 2010.
Rakesh Kumar, senior analyst at Meta Group, said he expected 60% of Meta clients - mainly blue-chip companies - to upgrade over the next three to four years.
"If everything is working [on Windows 2000] do not move unless there is a technical reason to upgrade," he said.