Self-employed

You will need to fill a T2125

In TurboTax Standard here is where you will access this information

1)  Go to the top tab called "INCOME" and answer yes to the first screen

2)  This will bring you to "Employment Expense Profile" select all box that apply's

3)  Fill all that apply's to your business expense and your computer purchase would fall under office expenses

Here is a link to tax tips on filing a T2125