What should I know before switching from Mac to PC?

Hi. I've been using Mac computers all my life but recently I've been wanting a PC since so many videogames are made for PCs. I currently use my Mac to play League of Legends, Hearthstone, Dofus, Minecraft, Rollercoaster Tycoon 3, and some other small games. My computer's specs are as follows:

Mac OSX version 10.6.8
Processor: 2.26 GHz Intel Core 2 Duo
Memory: 2 GB 1067 MHz DDR3

I want to get a computer that can run League of Legends, Skyrim, Aura Kingdom, Dragon's Nest, Maplestory, and any other small games optimally so I'm saving up for a PC that is good for gaming, I'm thinking a cyberpower Fangbook (Needs to be a laptop).
Another factor influencing my decision is that I have been using macs all my life and so has my family. I'm not sure how to go about using a PC since I've heard that they are not user friendly and can get viruses (never gotten a virus in my life). I also am on a budget, optimally below 800-900 dollars since I'm only 15 and don't have a job. (money is hard to come by for an unemployed teenager).
Any information to influence my decision or computer suggestions?

Get the specs for the games you want to play.
Sort out the most demanding hardware requirements.
You should find that the Video Graphics Card dedicated memory is the most important. Avoid Windows 8 if you can.
Then you try to find a machine that exceeds these specs because you want it to play the newer games as well.
EXAMPLE: For Skyrim:
-Windows 7/Vista/XP PC (32 or 64 bit)
-Quad-core Intel or AMD CPU processor
-4GB System RAM
-6GB free HDD (Hard disk drive) space
-DirectX 9.0c compatible NVIDIA or AMD ATI video card with 1GB of RAM: Nvidia GeForce GTX 260 or higher; ATI Radeon HD 4890 or higher
-DirectX compatible sound card
-Internet access for Steam activation