As far as programs go, if you're going to buy one Kaspersky has always been the best one in my humble opinion. Why? Well no security suite is flawless, but most security software, especially Symantec (Norton), and McAfee tend to use A LOT of system resources. Even if like me, you have a computer that can run the latest games maxed at 1080p, these programs will eat up a lot of your RAM, and choke performance. Kaspersky tends to use a lot less (It even has a game mode you can turn on if you do something exhaustive like editing video, or gaming. It reduces the workload while you do those things, then when your done uses what it needs.).
Beyond that the best thing you can do is change your surfing habits. Make sure you're using https: on your browser, not http:. The "s" ensures the browser uses security settings.
Don't go anywhere online that is off the beaten path. Stick to well respected, well known sites. Don't EVER use file sharing sites. ESPECIALLY STAY AWAY FROM TORRENTS. 9 times out of 10 you're going
to download an infected file. Possibly even a stealth infection your security software won't catch until it's too late.
It's also imperative you get ALL of the latest updates for your Operating System, software applications, and driver software for your hardware components (Motherboard, Video, Audio, Network cards), and peripherals (Printer, webcam, scanner, etc.) If you're on Windows 7, 8, or 8.1 most of these are done automatically (Assuming you left the setting on) but you may need to get the occasional part driver on your own (Ie go to Nvidia for a graphics card driver)
Why? Because in addition to improving performance of your computer, they include hotfixes to close security holes as they're discovered.
As far as that specific virus (Fake FBI) there are ways to get it out. It's just a pain in the rear depending on the version. Sometimes you (or a tech) can get into safe mode, manually find the files, and delete them. You can
also take the hard drive out of the computer, hook it up to another with a drive enclosure, and try to manually find the files, and delete them that way. Of course some versions hide a remote procedure file somewhere
on the drive to redownload the infection. In extreme cases you'll have to back up your files (assuming they're not infected), then reformat the hard disk (Basically puts it to factory settings, leaving NOTHING on it ie: YOU WILL LOSE ALL OF YOUR FILES IF THEY WEREN'T BACKED UP), then reinstall the Operating System (Windows/Macintosh/Linux), all of the updates, and then reinstalling/updating each of your programs (ie: Find your copy of office, reinstall. Find your copy of Photoshop, reinstall. etc.)
And again, you can buy an Apple if you want, but if you're on Windows doing so means you'll have to 1.) Rebuy whatever programs you use as an Apple version (unless you're going to install Windows on a second partition, and boot into Windows OR Mac. Though for some that defeats the purpose of using a Mac.) 2.) Assuming there IS an Apple version. Apple third party support is almost like Nintendo third party support. 3.) Make sure you can get a program that opens your file types. (In 99% of cases you can. Most have MS Office files, or Adobe PSD, or PDFs, and Jpg pictures.) 4.) You won't be all that safer from infection (There may be less Apple viruses but the number continues to climb) so you'd still want a security suite. 5.) You'll be paying 2x-4x the price of a comparable Windows machine.
Whatever you decide, good luck to you.