@OGIONIK,
... assuming you are in the US (I have no knowledge anywhere else).
First, you should get some tax forms. Businesses (even small ones) are supposed to file earning quarterly (i.e. every three months or so). The IRS will fine you if they find you are making money without filing quarterly. If you plan on making money (which I assume is the plan) you might want to see if you can get a financial advisor. If you only need a couple of hours a month at first, you may find someone at a reasonable price.
Second, there are lots of places for help for small businesses. When I started my business, I took a class (it was a couple of hundred bucks). I also went to the Small Business Association which hooked me up with some volunteer advisors. It was free advice from someone who knew what they were talking about.
Third... I work in software, not hardware. But, I think that certification will go a long way to helping you convince potential customers you are worth their trust. As you make money, getting Windows certifications seems like a good investment.
Fourth, successful business is about building a large customer base of people who think you are great. You will depend on repeat customers and word of mouth. This means you should work very hard to make sure that each customer is impressed.
Good luck.