Thats nice; Virus defs always get installed on OS drives so it will always be on C drive ; cannot change it
since this is a full download the initial download wil be large; after that it will be only incremental
once updated you can delete all the files in
C:\Documents and Settings\All Users\Application Data\Symantec\LiveUpdate\Downloads
you can also set the space to be used under
control pannel - Liveupdate (there is a setting to limit space)
what is the error its reporting....try rebooting the box ; it should fix it :)