The first iteration

The following is a list of helpful tools recommended by Microsoft at
www.microsoft.com/windows/antivirus-partners/windows-xp.aspx
which had no registration wall:

acs.pandasoftware.com/marketing/promo/IS09MICRO.exe
kasperskyusa.com/trials/kav8.0.0.506en.exe
global.ahnlab.com/global/products/myv3.html
global.ahnlab.com/global/product/down/AhnLab_V3_Internet_Security_2007.exe
download.bitdefender.com/windows/installer/en/bitdefender_antivirus.exe
trial.trendmicro.com/msvista/tis17/en-us/MSVista_TIS17_90Day_32Bit.exe
www.avg.com/filedir/inst/avg_free_stf_en_8_176a1400.exe
spftrl2.digitalriver.com/pub/symantec/2004/NAV2009_16.0_Build_0000001_OEM90_Microsoft.exe
www.k7computing.com/downloads/K7AV70/K7AV_Setup.exe
download4.quickheal.com/builds/eval2009/qhntevl.exe
download.zonealarm.com/bin/free/1472_zl/zaavSetup_en.exe

The weaknesses in this post is that the links are all explicitly
to .exe files which would be easy to filter if the browser or proxy
are untrusted. At the implementation stage (were these files to be
hosted elsewhere), the files could have unknown endings, such that the
user could re-name them to .exe once they have been saved locally.

Welcome to the Unbounded Touchtowns blog

Unbounded Touchdowns is the public face for the operational and research work of a small team exploring the frontiers of resiliency in personal ICT for non-experts.