EDIT and NOTE: this particular post is on antivirus and not on spyware remover.. just be aware of that... they're different ^^
avg doesnt detect less-common viruses and detects very few trojans.. if u want free and small av program, i recommend antivir,
www.free-av.com. it also uses much less HD space.
the only 2 things i hate about it are:
1. the update download is quite large.. every week maybe two there is engine update which is >1 MB I think... or around 1MB... im not using that av anymore and i forget
2. it doesnt use the same name as other av vendors, especially on those less-common viruses. and the site doesnt have virus description the way mcafee, norton and other big vendors do.. so its hard to check what kind virus it is exactly...
hmm.. the less-common viruses i mentioned were like trojans bundled in some programs...
for example, the kazaa lite in
http://kazaalite.tv/ contains trojan. it's not detected by AVG but is by antivir. but, antivir doesnt detect all of the trojans in it
and the infected file keeps recreating itself every reboot. i used kaspersky and it's gone.
EDIT: the domain kazaalite.tv has been removed now, apparently