Support will ended April 13th, 2010, and it is no longer able to get security updates.
The first step is to find out which version of the Windows operating system am I running? and what if you installed Service Packs.
Click the Start button, type winver in the search box, and then press Enter
This window displays the version and edition of Windows you're running. Each version of Windows comes in different editions with different features. This window also displays a service pack number if your version of Windows has been upgraded with a service pack.
You need at Service pack 1 or higher is you do not update you Vista you will have an unsupported Windows Version
What does it mean if my version of Windows is no longer supported?
An unsupported version of Windows will no longer receive software updates from Windows Update. These include security updates that can help protect your PC from harmful viruses, spyware, and other malicious software, which can steal your personal information. Windows Update also installs the latest software updates to improve the reliability of Windows—new drivers for your hardware and more.
You should always install the latest service packs from Microsoft for your version of Windows. You can download and install these through Windows Update.