You can't, you can't. Be clear on this; you CANNOT tell. Don't let anyone fool you into thinking there is some kind of "method". Even if you ask and the person answers honestly, you cannot tell. Very...
No, it is not possible to get AIDs from someone. It is very possible to get HIV from someone who has HIV. The only way to get HIV is from someone who has HIV. HIV is different than AIDs because HIV...
HIV - no. That basically only means that they're carrying the virus. AIDS however is when the immune system is beginning to fail, which leads to some visible changes, skin lesions among others.