Windows Vista Service Pack 1 has been out for quite a while now. If you are using Vista without Service Pack 1, then you should really consider updating! Service Packs are akin to makeovers of the operating system. This is the reason they are so large. They are filled with updates to the code, mostly revolving around fixes and patches for security and stability issues.
Not sure if you have Service Pack 1 (SP 1)? To find out, go to Start menu, aka 'Start Search' and type in 'cmd', then type 'ver'. If you have this, then you have Service Pack 1: Microsoft Windows [Version 6.0.6001]. 6001 is a reference to the build number.
Alternatively, go into the system applet within the Control Panel, seen under System and Maintenance. Better yet, go to the Start Search, and type 'system' and open the system applet to look for the version. You can also open "System Information", which will show you the version of Vista as well.
So, in a nutshell, if you only see "Windows Vista", then you are not on SP 1. Get it at Windows Update or download it here:
Service Pack 1