Paid for a computer looking to get my money back

What is the name of your state? California

I bought a computer for a friend, she said she would pay me back, now she feels she doesn't have to pay me back because we got into an argument. Is there anything I can do to get my money? Can I sue for the money, I put it on a card that is in my name. I would appreciate any advice.
Thank you,
Ben

you sue in small claims court (if the amount fits within the limitations) and as long as you can convince the judge the other person agreed to pay you back, you win.

Then, all you have to do is collect it.

Good luck with that part.