Responding to customer demand Dell has restarted selling new PCs with Windows XP installed on them.
Windows XP made its debut in 2001
The decision reverses a policy begun in January that meant Windows Vista was the only operating system available on almost all new home machines.
The change came after Dell's feedback site was swamped with calls for the return of the venerable software.
Now customers can opt for the Home or Professional version of XP on six models of Dell machines.
The four consumer versions of Windows Vista went on sale on 30 January and since then many PC makers have sold most of their machines with the software pre-loaded.
Since January Dell has been gradually phasing out the XP option on new PCs. By March Dell only sold two models in its extensive range with the XP operating system installed.
Dell is currently the second-largest PC seller in the world and has a 15.2% share of the overall PC market.
Dell changed the policy in response to pleas posted on its Ideastorm website which invites customers to post suggestions about how the PC maker can meet their needs.
The suggestion saying "Don't eliminate XP just yet" got almost 11,000 votes. In response Dell said it would offer the operating system on four models of Inspiron notebooks and two Dimension desktop PCs.
"This is really odd," said Michael Silver, research vice president at analysts Gartner. "On new PCs, consumers usually do want the latest and greatest."
Other analysts speculated that the reason consumers were keen on XP was because it was familiar and it worked well with many of the digital peripherals they owned.
In response Microsoft said that Dell was responding to a "small minority" of customers who had a very "specific" request.
It is not clear how long Dell will be able to keep its offer to install XP going. From the end of January 2008 PC makers will no longer be able to buy new licences for the operating system.