Quite possibly if you have the latest updates from norton....it could be a new virus they havnt got updates out for yet.
You are right...M$ never does send updates of any kind through email...neither does antivirus for that matter.
Check for updates on your office software..
In the windows update window...click office update.
There is a big patch that will block those attachments...you still get the email but are unable to open the attachment
(you will get something like.."outlook has blocked the following unsafe attachment virus.exe)
As far as blocking who the email comes from....likely won't work because most of those emails the virus spoofs (fakes) the from address.
Just keep deleting them.
A few good rules to go by...
If you dont know the person who sent it...delete it
MS does not send attachments...delete it
Antivirus does not send attachments...delete it
If you do know the sender...check with him/her to see if they did mean to send u attachment and what is the expected result if it is opened.
Save attachments to disk instead of opening them, scan em..if all clear..then open em.
Most people have no reason to accept attachments such as: .exe, .pif, .scr, .bat, .com, .vbs, and many many more but those are the most common carriers of viruses.
Also any attachments with double extensions are most certainly viruses...eg: funny pic.jpg.exe
Windows will ignore the .jpg (picture) and run the .exe (executable)
Hope that was some help