disble upnp in your router and upnp and ssdp discovery services in windows.
go to blackviper.com disable all other services related to "safe" in his services guide for your verison o/s.
boot into safe mode scan for viruses sand malware. some free ones are.... malwarebytes.org, http://www.avast.com/en-us/free-antivirus-download
reset your browser. don't use IE! chrome is safer and fastest.
firefox with noscript addon is safest!
disable all other unknown 3rd party addons.
download lastpass addon to store and automatically fill and/or create your passwords.
uninstall java. (if you absolutely need java for a certain site. use chrome just for that site. and use firefox, java disabled, and with noscript enabled for everything else)
make sure your adobe flash or/and reader is updated. download filehippo update checker. update everything.
Disable AUTORUN. diff then autoplay.....although you should disable that too. but AUTORUN, a viruses wet dream.
http://support.microsoft.com/kb/967715
just scroll all the way down and click the fix it button.
if anyone has any other suggestions....especially related to bf3. please add a reply.
Rich.
