Dell Dimension 8250 Problem

My 8250 is extremely slow. As soon as i start it up an error comes up..its all gibberish. It looks korean to me and i do not know where it came from. my computer is tooo slow for me to do anything on it. I want to reformat it but i have no past experiences and i cannot hire someone to do it for me. So if someone can please help me out here with some info id gladly appreciate it.

Specs:

Dell Dimenions 8250