DaveSimmons has good advice. If you want to start up a computer business try to find a niche market. Don't try to sell just vanilla OEMs because there are hundreds of other stores selling those. Sell PCs that are watercooled and are ready to be overclocked or something along those lines that would appeal to a hobbyist.
First, I would like to have a show of hands of all the people dispensing business advice who have never attempted to start a business, particularly selling computer hardware. Woohoo! Look at them all...not.
That pretty much rules out most people. I'm sure there are a couple people who have started a business, myself included.
As someone mentioned, a ton of overclocking and enthusiast businesses have come and gone.
There are really no unsaturated 'niche' markets in computer hardware. Anyone remember that company who sold 'pre-tested' and 'guaranteed' overclockable CPUs and CPU/Mobo/RAM combos? I forget the name, but they're gone, too. People who are enthusiasts are more likely to build their own PC, anyway.
For those few who aren't inclined to build their own, Alienware and Systemax (Tiger Systems) are offering some killer liquid-cooled, case-modded, gaming PC's for enthusiasts at difficult to beat pricing. vprMatrix, VisionPC, Cybertron, and a dozen others are offering 'enthusiast' class PC's as very attractive prices. Two dozen other 'smaller' companies are offering similar products. Heck, even Dell, HP, and Compaq offer some performance PC's at competitive prices.
It is NOT like it used to be 10 years ago. I personally know a dozen PC shops that were doing quite well, but folded under the crunch of competition from larger companies. The only ones left were those who had substantial access to capital or credit and can compete with the big OEMs by leveraging that purchasing power.
PC's are a commodity today, like televisions, VCR's and microwaves. You don't spend $150 to repair your $150 microwave, you replace it. Computers have become no different.
I certainly don't want to discourage anyone, just to give a better perspective of what you're dealing with and getting yourself into. You need capital today, a lot of it.
I owned a PC business primarily concentrating on hardware sales and custom builds, I got my ass handed to me on a platter by large volume companies. I lost several thousand dollars of my own money. Granted, that was my first mistake: never use your own money in a business venture.
But that was the ONLY significant mistake I made, other than trying to compete with the volume resellers in the first place without enough capital to even have a fighting chance. Its a ton of fun spending an hour of your time discussing computers and a custom build with a customer who "claims" he is interested in a custom built PC, only to have him reply to your price:
"Wow. I can get a similar PC from Gateway or Packard Bell for $200 less than that, and they offer a lot more software, toll-free tech support, a better warranty, and I don't have to wait two weeks. Can you match all that at their price?"
I had about 200 customers do that to me, that's roughly 200 hours of my time down the sh-tter for naught. If I sold all my hardware AT COST and not a penny over, I would still only MATCH the prices of volume resellers. It was very rare that I could beat them. Matching their price INCLUDING their warranty and software bundle? Not a chance.