I have been building the same pc for 12 years
I think every part has been upgraded at least 5 times, except the metal case.
I find, as a gamer, it is best to upgrade often, with semi bottom feeder parts.
Every year or so when I feel like upgrading, I have to do all the parts research over again. I usually go to here,
to find out what was currently a good part. then go to here,
http://www.newegg.com/ , to go shopping. Newegg has good prices, and a no hassle return policy if something goes wrong.
General tips
1 Buy an ASUS motherboard if possible. Better capacitors.
2 Get a 3 or 4 core processor for gaming.
3 Get an excellent cpu heatsink, and a cheap black edition (BE AMD) cpu. BE processors have an unlocked CPU multiplier. My current CPU is a BE 3 core AMD that cost only 72 $ 6 months ago. With the excellent heat sink, it runs great at 3 Ghz and all the games run smooth. Read a few of the many simple articles on the net on over clocking Black Edition AMD multi core CPUs. It is simple to learn , and gives you 150 $ processor kick for half price.
4 Never upgrade while all the games are smooth, the longer you wait to buy a part, the cheaper it gets.
5 If you buy and upgrade 100 $ parts every year, instead of buying 200 $ parts every 2 years, you will have a much faster game box most of the time, for your dollar. And you will have a shelf of extra parts that will prove invaluable for trouble shooting a dead system.
6 Get a can of spray electronic cleaner. Most dead boxes can be fixed by cleaning the vid card slot, and reinstalling the card. If still SOL, do the same with the memory sticks, and try to start it with just one stick first.
If it’s still crap, try what spare parts you have. I have had more power supplys fry than motherboards, so try that first. Every part on my box has gone crap at least once, except the case, which is on it’s 4th power supply.
I know it sounds stupid to clean the vid slot of a new board and keep plugging the card in and out, but that is the most common fix in my experience. I would try that 5 times in a row (power off, in out vid card, then reboot), minimum, before I’d try the next fix.
Most importantly, do not expect a newly built box to fire up first try. 50/50 at best IMHO.
Lot’s of tiny contacts to maybe not contact at the start. Just keep at it, and remember that it’s not a parrot. It only looks dead, but it’s almost always just a part that is dead, not the rest of the parts.