The following Microsoft KB article applies to Windows XP, Vista and Windows 7 both 32bit and 64bit editions.
Be careful you download the correct version for your computer.
Since that day, I have tried to update MSE numerous times but get a reading that it could not install updates because of internet or network connectivity problems. This happens to a lot of people — so much so that Microsoft has a special page where you can download the updates manually.
If you’re not sure if you have 32bit or 64bit, right-click “Computer” (on the start menu) and choose “Properties”.
It will tell you if you have 32bit Windows or 64bit Windows. At the top it says Windows XP, Windows Vista, and Windows 7. via Cloudeight Info Ave Premium – Computer tips and tricks newsletter.
Follow the guide below to change the registry key to allow MSE to check and update virus and spyware definitions signature database every few hours.
Ability to perform and update process more frequently also able to solve the issue when MSE does not update its definitions database automatically.