Microsoft has released a major update for its Windows Vista operating system.
The update will fix bugs and improve software drivers
Vista Service Pack 2 fixes a number of bugs in the software.
The download is being made available publicly, however it is currently only available as a Beta version.
The release is intended for computing enthusiasts and IT professionals to use during a testing phase.
A final version of SP2 is due in early 2009.
The update improves Vista's handling of software drivers, used to make external devices work with PCs.
WiFi and Bluetooth performance is also enhanced.
Power efficiency is improved by a claimed 10% and it also contains several hundred bug fixes.
Windows Vista has been criticised since its release in January 2007.
Some users have complained that the system is slow, prone to crashing and overly demanding of processing power and memory.
The stigma attached to Vista became so problematic that in July 2008, Microsoft launched an advertising campaign known as the Mojave project.
PC users were asked to use a 'new' operating system known as Mojave, having been told it was a pre-release trial.
Many gave it higher approval ratings than Vista.
It was later revealed to participants that Mojave was, in fact, Vista.
However, Microsoft is also developing Windows 7. Some reports have suggested it could be available as early as 2009.
But Microsoft has not confirmed a launch date yet.
The new operating system features support for touchscreen devices, handwriting and speech recognition.
Early previews have received broadly a favourable response from computer journalists.