To add to your toolkit I highly recommend these 2 free Anti-malware offerings plus a free firewall that I use and found to be of the highest standards.
Avira anti-virus free version:http://www.free-av.de/en/index.html
For spyware plus other goodies try free SpyBot Search and Destroyhttp://www.safer-networking.org/en/download/index.html
Both are free and both have auto update facility and both do their job well and are of course multilingual.
I recommend you do a malware scan before a format just to see if anything comes up.
To cap it all off one of the very best firewalls is the free offering from Comodo the SSL certificate people - don't select the pro version as it is $$$, the free version does all that most people will ever need.http://www.personalfirewall.comodo.com/