cannot update definitions?

[Tom]

I once updated the definitions successfuly.
last time,when the new definitions were being
download,system crashed,then i can not update either the
definition or the software.the auto update screen always
show "most recently definitions installed". and the
summary screen shows definitions(ver 5691) is up-to-date.

Is it really the newest definitions ?

 

[Bill Sanderson]

Yes, those definitions are current as of this writing. The definition
updates vary in frequency.

Take a look at this KB article for some historical information:

http://support.microsoft.com/default.aspx?scid=kb;en-us;892519