Hi please follow the steps below it will give you an idea if the machine is having a proble to connect to liveupdate server or is it not able to install the updateds.. Once you know the problem thing what to do.
-Go to control panal double click symantec liveupdate..
- make it Interactive Mode
- Then go start / run & type luall.exe then click on..
- A liveupdate wizard will start check in the wizard if you see the def & do next .