Even if you did just buy a fancy computer, there are some measures you need to take to benefit you in the long run. Here's some beginners tips.
Install an ad/tracker blocker.
This will help keep third-party organizations from accessing your your private information. I suggest applications like Adblock+ or Privdog. I prefer Privdog over Adblock because Privdog gives you an accurate update on the amount of Ad networks, trackers, 3rd party networks and cookies it has blocked. In a single browsing session, Privdog blocks about 500-1000 threats.
A good antivirus software.
Look here, the Norton Antivirus or Windows Defender that came with your PC just isn't that great.
I suggest MalwareBytes or System Mechanic. Malwarebytes is free, while SystemMechanic is not. Both work together excellently. An advantage of SystemMechanic is GPU monitoring, Hard Drive Repair, and Registry Repair. System Mechanic is by-far the best Tune-Up software for an old, infected PC. I cleaned 30gb of viruses off of my old computer with it.
Question Everything. Prior to downloading things, check sources and make sure they are reliable. Obviously, don't open emails from strangers.
Keep your system clean! (literally). An old system can overheat from too much dust or debris in the ventilation system. An easy fix is to buy some compressed air from the store and blow it into your vents.
