I have been a PC gamer ever since I was a toddler. My parents moved on to become Mac heathens. However, they are opening a business very soon and the software they are using for many different things will run on Windows. Because I'm the only one in my family who stayed true to the master race (and who has used a PC in the last 10 years) they want me to help them find a few things. I'm a gamer, not a business woman, so I need your help. They need:

A decent prebuilt (sigh) PC with a good warranty that is around $500-$600

2 tablets that can run Windows 8.1

A good virus protection program for a business

I would really appreciate some suggestions. Thank you if you can help me!