What is the best PC I can get for low level graphic design?

[terenkleon]

I am starting out in graphic design, illustrating children's books, etc. I use Serif software, which is similar to Photoshop. I also use the internet heavily, having multiple programs/windows running at one time. I do not know a lot about computers, so if you give me all the specs, please be very clear and if possible send me a link to where I can buy/build the proper computer. I want a PC (not a mac) and a Desktop (not a laptop). And I'm hoping to stay under $600.
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