Microsoft Security Essentials is a much better choice among freeware AV packages. You would have noticed, that it updates its virus definitions on first launch and it could be a bit problem on a PC, which is not connected to Internet. But you can download its offline updates appropriate for your version of Windows.
You can download the Microsoft Security Essentials from here. Microsoft Security Essentials v2.1
1. Download the latest virus and anti-malware definition update files.
- Click Here to download the file for a 32-bit (x86-based) version of Windows.
- Click Here to download the file for a 64-bit version of Windows.
2. The update files are executable files and can be installed easily without much interaction.
To verify the status MSE: Open Microsoft Security Essentials, click Update, and then see the virus and anti-malware definitions status.