Yes I can't 

Is a positive answer to a negative question

taking simply mathematical principals, two positives make a positive, two negatives makes a positive, so a negative combined with a positive leaves a negative.

so a question like, "can't you fix that computer?" requires the response, "Yes I can't" if indeed, you cannot do so, but "no, I can" if you are able to.

simple really

Yes I can't by progrelayer April 26, 2009

Yes I Can't 

The request for something, but usually ends up in a bizzare response from one's perspective.

Can I go to the mall?
Response: Yes you can't

Can you go to the party this weekend?

Response: Yes I can't

Yes I Can't by Young Shady March 15, 2009