Whatever you do, do not use Kapersky. Its Russian.

I will list some steps, not all at
once.

Applying any and all updates available for your system is the first line of defense. After that, you can consider other security additions.

1. Data backup: a USB terabyte drive is very affordable. Use the built-in Time Machine or down Carbon Copy Cleaner

2. Software updates: they have some scans built in.

3. Do not use Kapersky software ever. MacWorld recommends it which I think is totally irresponsible.

4. Stick with either Intego, McAfee or Norton. Only download from the App Store. ( Do not use sites recommended by Google or any search engine. They don’t pass my kosher test. )

5. I believe you have some Mac seller stores near you: Best Buy and Guitar World. Go there and get a decent chat.

6. Additional stuff is use First Aid in Disk Utility in the folder Applications / Utilities folder

Note:
once upon a time, i was up to date on key Mac gossip. I would like you to visit one of those stores instead of doing any immediate downloads.

once again, do not download except from Apple App Store. (there are exceptions but i don’t know which right now)

So, a few things to keep in mind -

1) Do all the OS security updates. They have responses to a variety of malware.

2) NEVER use Kaspersky (Russian) or Norton (so intrusive and so slowing of your machine that it might as well be malware itself).

3) There are great free products to use whenever you need a scan. The best are:
- Malwarebytes (free version is fast and lightweight, and detects are removes problems. Nothing stays on your system with "continuing" protection unless you pay for the premium. I don't. If I need to do a scan, it's once in a blue moon. It has always done extremely well for me.)
- AVG Antivirus (this can stay resident on your machine, but it doesn't interfere and slow you down like some other products)
- Comodo Antivirus (similar to AVG. I don't like it as much, so I use AVG out of these two options)