I have been using MSE (Microsoft Security Essentials)
for long time and I am very happy with its performance
..It's lite,fast and work great..
So if you want to download it's Offline Updates
to Install on other PC without internet you need to download the MSE virus and spyware definition update file,For 32 Bit OS Download from here :-
For 64 Bit OS Download from here :-
Run it and Enjoy