I want to build a gaming pc with a budget of around 1000-1500, have no idea where to start and what works with what can someone give me specs that'll work really well with all the sims games, mass effect etc
Because I don't want to waste my money on a tower that will only play some of these.
I'd suggest you look at the system requirements for the games you want to play then research a motherboard + CPU + RAM + GPU/Graphics Card + PSU combo that exceeds those requirements. If you just get the recommended settings, they are most likely the LEAST amount for RAM, etc… that you will need so by exceeding you'll have enough for your build.
Another thought, once you find what you want and priced it, check local deals on "gaming pc's" and see if you can get a better deal (keep in mind you can buy one that comes close and swap out what you need IF it's cheaper to go that route).
I just built a pc I used pcpartpicker.com
They have comparability options that will only list parts that are comparable with the parts u have already picked. When I built mine the case ended up being incomparable with my liquid cooling so I emailed pcpart picker just to let them know what had happened so they could fix it for the next person and they ended up offering to pay for the case and a replacement case. So I would highly recommended pcpartpicker to u for ur project
core i3, nvidia 420 GT, 6 GB ram is better
Go to the website canirunit.com and see what the requirements are for your games.