PC Building Help Needed?

1. Memory, a little more is always good for gaming. (make sure your M/board supports the memory you get). You are right about the graphics card and processor.

2.Specifications should be listed wherever you buy a M/board from. It will tell you the socket type, this is important as it must match the processor you want.
The specs should also tell you what speed memory you can use. Make sure that the hard drive you are using has the correct connection also, this should also be mentioned iun the specs for both.

3. Each of the components are attached to the M/board and so only have to be compatible with it.

4. More power is good, but realistically if you are running one graphics card you will not need anything more than 650 - 800 W. Too little is bad, but so is a poor PSU, get a good one, cheap and nasty are two words that go together for a reason. Modular PSU's are a little more expensive much easier to fit.

5 .i7 or i5 will be fine, it is the speed that they run at and the number of cores that is important, obviously 4 (quad) is better than two! (dual)

6. You can't some parts are better than others and still can be cheaper, just get all the parts that are compatible and within your price range and relax, and be very careful when putting the parts in.

7. Without knowing your price range it is hard for me to suggest the parts you want.

Tips: Earth yourself, always make sure you don't use too much force fitting a part, (perhaps watch a youtube video on "How to..."), relax, take your time, make sure everything is plugged in, make sure everything is bedded in, make sure you have an OS ready for it, put all the drivers onto a flash drive (memory stick) if you can, it saves a lot of time.

It really is the easiest part of a new build, it is installing all of the drivers and software that is the hardest part.
Techies like to make you think it is a dark art, believe me, once you have done one you'll wonder why you were so worried and afterwards you will be able to do it in a fraction of the time.

Good luck!