Included among the updates for Windows 7 are:
Updated multiple interface USB devices, updates for changes in daylight savings time in several countries, Windows Media center fixes, enhanced compatibility with memory cards over 32GB, and Internet Explorer compatibility with JSON interoperability in conformance with the new ECMAScript, fifth edition standard, as well as a fix for Virtual PC on PCs running Intel's Westmere family processors.
Other updates were issued by Microsoft in this latest update group as well.
If your PC is not set to automatically download and / or install patches from Windows Update (or Microsoft Update), especially if you haven't visited or checked lately, you can find a direct link from the Start menu on most PCs.
Special Note: Windows XP users should be sure they are currently using Service Pack 3 as support for Service Pack 2 is set is expire soon:
Still not sure about Windows 7? A 90-day trial of Windows 7 Enterprise is still available at TechNet here as well as a variety of trial packages and the latest beta of Office Professional Plus 2010.
Another resource for the latest downloads and / or security updates from Microsoft can be found at the Microsoft Download Center here.