If you want to find the best parts, overclockers.com forums will guide you on the right parts.
Overclockers Forums. If you go there, be prepared to do 90% of the learning using the search function, and the rest is educated posts. If you go in saying "
HEY how much artic silver should I put on the CPU??" then you haven't done your homework and may be treated as such. You will do some work, but the knowledge you gain will stay with you forever. Those guys (and at xtremesystems) test the everliving shit out of parts routinely, including soldering new resistors on voltage reg circuits and such to bring speeds far out of spec, along with other insane behavior. I do some of this myself, but that's for another day

. Anyways, point is they test so much crap that the parts they buy will almost certainly run for you very nicely at stock or slightly overclocked speeds, but there again, do your homework
The good thing about PCs is you almost can't put something into the wrong socket. I say almost, because I've seen people actually bend the motherboard to force ram in backwards, and when it booted they fried the platform parts (cpu, ram, mobo).
DOA and warranty items happen, but if you deal with a site like newegg, you never regret it. I've worked with newegg so many times, and have even been allowed to return parts outside of the 30 day return policy. You just need to get a rep on the phone (always
talk to a person, they listen - no email) and they will work with you. On a tangent, for OEM upgrades such as that dell,
MemoryX.Net has always worked with me, to the extreme. I've even swapped out ram in a server 2 years later with them, and that was over compatibility issues, not dead parts! 2 years! Those are my experiences, others will have their own favorite vendors, of course.
Anyways, several of us here can help you pick out parts too. I'm an active overclocker and watercooler, and I focus on maximum speed over the long term generally, as opposed to the LN2 guys that prefer to break records. I'm also a big DIY guy, especially on the hardware side. One way or another, you'll learn whatever you want to know
