What I would reccommend doing witha $1500 budget on a build your own computer mission, is to get a very strong core setup, but leave some room for expansion. A nice 24" widescreen LCD monitor is going to eat about $300 out of that budget right away, so we'll assume $1,200 for the build. The things that are the most pain in the ass to change out are, in order: Case, Motherboard, Power Supply then CPU. everthing else is pretty interchangeable.
Of all the components you buy, chances are your case will be the one you have longest (10 years or more). So first you want to go with a case that has plenty of room, that you like the look of, thats well built, and ideally made of aluminum or other lightweight construction to make it easier to work with. Cost is important, but on this item I reccommend getting what you like rather than what is cheapest because you will be stuck with it for quite some time. That being said, there are a definite range of options, with one of the cheapest "good" cases being the Cooler Master CM 690 version 1 or 2. Both can be found around the $70 mark, with the 2 being somewhat prefferable. Or you can go with something higher end. Performance-pcs.com has a really good selection of cases. I don't necessarily reccomend buying your case form them, but it is a good place to look and see what is truly out there and about what they cost.
Motherboard/processor, I tend to prefer Intel. AMD tends to be a bit lower in price, for a bit lower performance on average. That's what I know best, so thats what I'll reccommend.
Power supply, for a gaming PC, you want a very robust, higher wattage PSU even if you aren't using all of it initially. Right now Multiple graphic card rendering systems are fairly affordable and popular, so even if you start with just one video card, you'll want to ensure that you have sufficeint juice available to upgrade later.
The rest of the internal components in your old computer you can effectivly scrap. The HDD is probably usable, but its also probably an older IDE drive, which means it is more of a pain in the ass to set up, and it has much more time on its bearings. Hard drives WILL eventually fail, it's not a question of IF, but When. You are much better off getting a new SATA drive. no jumpers to deal with, no ribbon cables to block airflow, etc. And they are fairly cheap these days.
Optical drive: DVD burners average around $30 for a good one these days. Blue ray burners are down around $125. Either will be faster than the one in your old computer.
So, with that in mind, here's what I would build right now on that budget: Monitor:
Samsung 24 inch HDMI widescreen (or equivelent) ($269) http://www.newegg.com/Product/Product.aspx?Item=N82E16824001331
Notes: Get that locally if you can. Shipping will be a pain and returning a monitor with a stuck pixle is much easier at a store. You also want to see the LCD in person before you buy it. This is the same LCD core they use in Dell 24 inch widescreens. The Dell ones have better articulating stands though for height adjustment. Case:
COOLER MASTER CM 690 II ($79) http://www.newegg.com/Product/Product.aspx?Item=N82E16811119216
Decent aize, low price. Good all around case. Motherboard:
Asus P6X58D Premium LGA 1366 Intel ($285) http://www.newegg.com/Product/Product.aspx?Item=N82E16813131614
USB 3.0, Sat 6 GB / second controller Processor:
Intel Core i7 3.06 Quad core with Hyperthreading ($298) http://www.newegg.com/Product/Product.aspx?Item=N82E16819115211
Fast enough, if you need more speed than that, the next major step up would be one of the $1,000 hexacore processors. the others are just incremental steps ($200 more for another 200 Mhz? Nope) Ram:
4Gb Corsair DDR3 ($74) http://www.newegg.com/Product/Product.aspx?Item=N82E16820145251
Upgrade to 12Gb as funding permits later PSU:
Antec 850 Watt PSU ($150) http://www.newegg.com/Product/Product.aspx?Item=N82E16817371009
You could go with a less expensive 750, this would give you enough headroom to run dual video cards if you choose later. Hard drive:
Western Digital 160GB 7,200 RPM HDD ($38) http://www.newegg.com/Product/Product.aspx?Item=N82E16822136075
It's a hard drive. There are faster ones but I already used up all the allocated budget. Video card:
Evga 470 GTX video cards in SLI mode ($$259) http://www.newegg.com/Product/Product.aspx?Item=N82E16814130550
Upper end card, one of the faster ones for FFXIV at the moment. There are also decent ATI/AMD cards out there if you choose to go that route. A year or two from now, when prices come down, grab another one of these for a secondary card. Optical disk:
LG 22x DVD burner wth lightscrbe - ($17) http://www.newegg.com/Product/Product.aspx?Item=N82E16827136168 Operating system:
Windows 7 64 bit Pro ($69)
As you mentioned Fafsa, I assume you are a student. In that case get it here: http://www.microsoft.com/student/en/us/software/windows/default.aspx
Use your old XP license as the base key for the upgrade. You want the 64 bit version, not the 32 bit.
For a total of $1538 with the monitor.
For tools you will need a phillips head screw driver, a tube of Artic Silver (http://www.newegg.com/Product/Product.aspx?Item=N82E16835100007)
just in case you ahve to pull and resea the processor heatsync, possibly some paper towels and rubbing alchohol for that same scenario, and some zip ties to keep the cables neat in the case.Other than that, the Case comes with all the mounting hardware, the motherboard comes with all the internal cabling except power cables, and the power supply has those. The most difficult part of the entire process is installing the processor. The pins in the CPU socket are veeeery fragile and easy to damage. Worst case scenaio if you damage them though is you send the board back and get a new one, which delays your computer. If possible, get someone you know locally who builds computers to watch over your first build. Also make sure you install the brass standoffs under the motherboard. I always add that one just in case because I know someone who didn't once...
Other than that, everyting is pretty easy to follow. Ram is easy to install, so are video cards. Motherboard you instal the backplate, then screw it down with enough force to be finger tight, then maybe 1/8th urn further as you don't want to crask the board. CPU, you just need to be careful to set it in without digging the corner of the processor into the pins, and make sure you latch it in properly. The heat sync fan is a pain in the ass to install the first time. follow the instructiosn tat come with the CPU and it should be doable though. You'll see what I mean when you get it. Aside fromt aht, its just make sure everything gets plugged in that needs to be (ones that get forgot often are the 8 pin "Core voltage" motherboard power supply connector and the PCI express power leads on the video card) The Asus manual that comes with your motherboard has good instructions. read through all the manuals a few times before you start and you'll be fine.
Feel free toPost here or PM me if you have any questions