This is showing repeatedly in security history:
Rule "Default Block Microsoft Windows 2000 SMB" blocked communication
local address: All local network adapters (port 445)). process name is system.
Norton says severity is low no action required. but I found this http://www.microsoft.com/technet/security/advisory/975497.mspx
and this http://news.cnet.com/8301-27080_3-10371176-245.html
apparently this security hole is due to be fixed with the latest windows security updates to be released next week, and microsoft have known about it for some time..
Also getting this message in security history:
Rule "Default Block Windows File sharing" Blocked communication Local address 169:254.??.?? (Port(139)) Process name is system
and this also "Default Block EMAP Blocked communication local address All network adapters (portdcom(135)) process name is C:|Windows|System32|svhost.exe
Does this look like someone is trying to gain access to my computer?