If you are classified as an employee, you can't deduct the cost(s) of your work computer.
If you're self-employed, however, you can either write it off as a business expense under the business safe harbor election (up to $2,500) or treat it as a business asset. As a business asset, you have a choice between deducting depreciation for the next 5 years or the full cost in the year you acquired it (assuming it qualifies for Section 179 treatment).
