I will not disagree with Rednose in any way, but if you have a current avast version with the updates way out of date, there is another option.
The major geeks websites has complete avast updates, the file size as of yesterday was 29.1 MB.
The copy paste is ------ avast! Virus Definitions October 28, 2009 [ 29.1 MB | Freeware | Win All]
Not only does major Geeks have such a links for Avast on a very three or four days basis, but they also do the same
for a wide variety of AV's.
Of course someone has to download it and burn it to CD-r or pen drive, but if nothing else, most public libraries will allow
anyone to do it with library fast broadband.