Since a gram of prevention is worth a kilo of cure, I'd suggest using Firefox as default browser, with the Noscript add-on, and AdblockPlus.
NoScript will prevent drive-by downloads (from infected webpages) from even recognising that your browser is there.
I also use Avast, have MBAM and SAS (superantispyware) available for Bad Times (hasn't happened in a few years, now) and Secunia PSI, to monitor any out of date or vulnerable software. Windows and other software installed is kept scrupulously up to date. Windows firewall has proved more than adequate with this setup.
Some kind of imaging software and an external drive is worthwhile. Macrium do a free one called Reflect. Others include Acronis, and the old but reportedly good Norton Ghost.(or Norton Go back.)
In the event you get an actual infection and need to use tools to clean it, I'd suggest getting those, under knowledgeable guidance from a helper at a security forum, at the time they are needed.