I personally use the KiXtart scripting language { http://kixtart.org , KiXtart is
CareWare }
but, you can do this in DOS in a BAT file or under the NT Commnd Interpreter in a CMD file
or any scripting language.

The following assumes Ad-aware is in; C:\Program Files\Lavasoft\Ad-aware SE

UPDATE.BAT
-------------
@echo off
cd "C:\Program Files\Lavasoft\Ad-aware SE"
wget -N http://download.lavasoft.com/public/defs.zip
unzip -j -o defs.zip

I place the following utilities in the PATH, usually in; %windir%

Then you can use the System Task Scheduler to run the batch file whenever you want it to.

Utilities:
--------------
InfoZip UNZIP utility...
ftp://tug.ctan.org/tex-archive/tools/zip/info-zip/WIN32

WGET utility...
http://users.ugent.be/~bpuype/cgi-bi...=wget/wget.exe


--
Dave
http://www.claymania.com/removal-trojan-adware.html
Multi-AV - http://www.pctipp.ch/downloads/dl/35905.asp