If you use "Guai ga warui" in person, means sick, physical problem. When your computer doesn't work properly, you can also say " pasokon wa guai ga warui"

私は具合が悪いです。= Watashi wa guai ga warui desu . I[topic], state[subj] bad is. = I'm in a bad condition. "ga" is the particles used to show what does the i-adjective (悪い) modifies (the noun 具合).

It means "He/she doesn't feel well/good." or "He/she is sick." **physically**. It's often used together with 体が, such as 体の具合が悪い. For example, このところ体の具合が悪い。(I haven't been feeling well lately) Other than that, you could say something is in poor condition, not working well or something is wrong with an object. For example, クラッチの具合が悪いです。(The clutch isn't working right.) ドライヤーの具合が悪いのですが。(There's somthing wrong with the drier.)