To test RAM, I use Memtest86+ (or something like that, I'm too lazy to look it up and link it.) For Antivirus, I've been using NOD32 for a couple years, and it has been AWESOME! Daily updates, email protection, MS office protection, daily updates. Pretty much JUST what you need, but not more than you need. It doesn't hog up a bunch of resources that slows the computer down (like Norton does?) It's been one of the highest rated with low overhead for a while now. NO AV program will catch it all, you really need to run one all the time, and regularly run a manual scan with others, even the free ones are great for this! Good luck!