The following links may be useful to you when it comes to protecting your computer.
The first link is to an article that puts things into perspective, and explains why spending big $$ on McAfee and Norton is not necessary.
The remainder all take you to where you can download useful programmes.
The Microsoft Security Essentials is very important, you just need to set it up to scan your computer on a regular basis. Mine is set to scan every morning at 5:00am. It is a ‘set and forget’ programme. Be sure to have it automatically search for updates and download them.
The rest are all good too, I like to have a few because if one of them finds something and can’t fix it, one of your other ones might be able to.
I have a folder called ‘anti-malware utilities and tune-up tools’ on my desktop where I keep all these things. I tend to use at least one of them every day, and I switch from one to the other.
Some of them ask for donations, and if you try one and like it, then why not! They all provide a useful function.
Obviously I am not prepared to guarantee your experience with any or all of these, but I use them myself and have been very pleased with them so far.