Help me upgrade a PC, please.

I’ve got an almost-6-year old Alienware as my primary Windows box. It’s been a real trooper, and I’ve had no significant problems with it. It’s starting to get a little long in the tooth, though, and I’m torn between scrapping it for a new box, building my own new box, or making some upgrades to this one. Here’s the current critical components:
[li]ASUS P4C800-E motherboard[/li][li]Intel Pentium 4, 3.0 GHz processor[/li][li]2 GB DDRAM TWINX 2048-3200PT RT (thought I had more; I’m going to have to look at that more)[/li][li]Radeon X1600 Pro 512MB AGP Video Card (upgrade from original)[/li][li]Creative SB Audigy 2 ZS Sound Card[/li][li]420 Watt Power Supply[/li][li]Seagate Barracude 120GB Serial ATA hard drive[/li][li]Second 128 GB hard drive (can’t remember detail; I pulled it out of another computer)[/li][/ul]All this is housed in a standard Alienware Area-51 full tower case.

I’m not exactly a power user. For the most part it’s a web-surfing, letter-writing, Quicken-running occasional game-running machine. As for the games, I tend to be a couple of years behind the curve. I haven’t finished Halo 2 yet (partially because the machine seems to be limping along on this), and I still haven’t started Half-Life 2. I like FPSs, but I don’t spend a lot of time playing games, so I tend to pick them up cheap a while after they become popular.

The last time I priced out some components, the difference between build-my-own and buy pre-made wasn’t as significant as it used to be so I’m leaning toward Frankensteining what I’ve got now.

To me, the obvious places to start are the motherboard/CPU combo, RAM, and video card. Unfortunately, every time I start looking at new components, I get completely overwhelmed by the different CPU/motherboard combos and I determine to limp along for a little while more.

So my first question is, based on the motherboard I’ve got in there now, will the case accommodate modern motherboards (I assume it will). Assuming I want something current that I can get a few years of use out of, but not necessarily bleeding-edge, anyone have recommendations?

I assume that once I settle on a motherboard/CPU, I will be better able to focus my attention on the other components and they’ll start to fall into place. Maybe I’ll be back to ask for more help once I get there, but let’s focus on the brains of the box first. I’ve replaced/installed virtually every component in a PC over the years (except the motherboard) so I’m not afraid to get my hands dirty (provided soldering’s not involved). I’m just behind the times on CPU technology.

So, anyone want to toss out some suggestions?

Well the big choice right now is between socket 775(quad core and core two duo) and 1156/1366.(i5/i7) Right now it’s pretty much middle of the change over.775 is the older of the two, but still has some good life and will serve people well for at least two more years. i7 However if you kept your machine for 6 years, you might want to look into the new stuff. Its old enough that the shiny and new premium has fallen off and it is some fairly good prices.

i5 and I7 are both new technologies that will be supported for a long time. i7 is more of a higher end performance market, while i5 is a more standard perfomance/budget aware line right now.

Coincidentally, I’m going to be doing the same thing soon, upgrading a six-year-old P4 3.0GHz.

My plan last time was that I bought a CPU about two steps down from the top end. I.e., the $300 one instead of the $1000 one. Nowadays, that would be something like the i7-920. I’m not a hardcore shoot-em-up gamer, but I dabble, and I figure that even if I don’t need the chip speed now, I might in three or four years.

There are so many motherboards out there. Asus and Gigabyte are names that I know, and I’ll probably pick one of those.

I forgot that I’m going to need to upgrade my RAM too. Dammit. How much RAM are the cool kids using these days?

Where I need help is the video card. The technology has totally changed since 2003. Apparently you can install them in groups now? For someone whose gaming runs more (but not exclusively) toward point-and-click adventures and mysteries rather than MMORPGs and Call of Duty, am I OK similarly getting a card that’s a couple steps down from the top? NVIDIA 275? Radeon 48xx as opposed to 57xx? Is there any advantage to linking two or more cheaper cards as opposed to one higher-end one?

Finally, power supply. I currently have a 500W. Will that suffice? It probably doesn’t have a plug to fit a modern video card; will the card come with an adapter?

Some recent threads with good advice and resource links.

Computer build!
Is it even practical/possible to build a PC these days?
Critique my planned computer build please.
I want to build my own computer and I’m scared.

Given that list, my first suggestion would be to upgrade to 4GB of memory. You don’t mention the OS (probably Win XP), but that would give you the most bang for the buck.

Before I’d consider a motherboard/CPU change (effectively a rebuild of the machine), I would decide on a specific answer to “What do I want my machine to do that it can’t do now?”