A:
The first thing that you need to decide on a new computer, whether you're on a budget or not, is exactly what you want to do with your new computer. When you're armed with this information, a salesman won't be able to sell you more computer than you need simply to pocket a larger commission.
Many people start to look for a computer by looking for a certain name brand. My advice would be to only worry about name brand if there is a particular brand of computer that you have had good luck with in the past. For instance, until my current computer (which I built), I've always stuck with HP. Why? Because my first computer was an HP and I've always had exceptionally good luck with them - although my laptop, a ten year old Dell, is doing just fine. One brand for budget-minded users, E-machine, used to be a bad brand. They were, however, purchased by Gateway a few years back and have been a fine budget machine since then.
You also need to decide if you want a desktop or a laptop. If you need portability, get a laptop. Be prepared, though, to pay more money for less machine if you do, and for the fact that laptops are generally harder and more expensive to upgrade than desktops. Otherwise, stick with a desktop.
The key features to look for in a new computer, as you mentioned, are hard drive size, processor and RAM. Another thing to look for, though, especially if you want to game, is video card.
Hard drive:
When I sold computers for a living and people would ask me the difference between hard drive and RAM, I would explain it like this: A hard drive is where you store all of your stuff. It's kind of like the closet of your computer.
Over the last several years, hard drives have gotten much, much larger and much less expensive, so it's really not going to kill you financially to get a hard drive of 500 gigabytes or even a terabyte, which is a huge amount storage space. The larger the drive, the more music, photos, games, etc. you can store. One thing to bear in mind, however, is that the larger the drive is and the fuller it gets, the longer it can take to retrieve your information, including the time that it takes your computer to access your operating system. For this reason, another alternative is to get a computer with a small hard drive that basically just holds your operating system and your programs, and an external hard drive to store all of your stuff. My desktop, for instance, has an eighty gig internal drive, and I use a five hundred gig external hard drive to store my documents. This gives you the added advantage, if you use more than one computer, to move your documents easily between the two.
Processor:
Do yourself a favor and don't skimp on the processor. Having said that, make sure that you get one that can handle the new programs that are coming out. As processors get more powerful, software manufacturers are writing programs to take advantage of that power. The better your processor is, the longer it will take for your computer to become obsolete. Unless you are doing HD video editing or playing the latest iteration of World of Warcraft, any of the Intel Core series should be fine, but if you want to future-proof your machine and can afford it, it certainly wouldn't hurt to get something with the i7.
RAM:
The amount of RAM that you have determines the amount of information that you can have open on your desktop at one time without lag. Most pre-built computers these days are coming with a significant amount of RAM. Again, with the prices on RAM dropping significantly over the last several years, RAM doesn't increase the computer's price by any large amount. Four gigs of RAM seems to be the standard for budget machines right now, although if you're gaming or doing HD video editing, you may want more. The more that you have, the faster these applications will run.
Another thing to bear in mind for future upgrading is what type of RAM you get. The Intel Core series of processors runs DDR2 ram, which increases in multiples of two (two, four, six and eight gigs), while the i7 runs DDR3, which increases in multiples of three.
Video card:
The stock video card included with most pre-built PC's should be plenty to run basic games, as well as features like Windows Aero. Watching or editing HD video or playing graphics-intensive games may require a better video card, though. Upgrading your video card can run you into the hundreds or even thousands of dollars, though, I'd suggest asking a friend who does similar things with his PC that you'd like to do what video card he's running. Friends will always offer better advice than salesman.
