Can someone legally take back a gift if it is financed in their name?

If your ex gave  you the computer as an outright gift, he cannot take it back.  The problem is that this is a he said/she said situation, with no guarantee as to who a Judge or jury will believe.  He may say that he didn't give you the laptop, but only allowed you to use it, or that he only gave you the first few payments on the laptop and you were supposed to make the remaining payments, or that he only loaned you the money to buy the laptop, but you were supposed to pay him back.  While criminal charges are theoretically possible, they are very unlikely in this domestic, penny-ante he said/she said situation, but a civil suit is more possible.