12v, 0.12A
Those are the power requirements of the fan. You might want to look up the actual brand and model number for some airflow&noise specs though.

Did you just cut the wires or does it have a connector? What do you want to do with it?

The wires should be red and black and with that information you should know how to use it.

Seriously, read some books on the topic if you want to play around with electronics.

And no, you are not going to get very far running the fan off 5v, 500mA (a USB port)
You would be best off running it from a suitable "wall wart"(ad to dc adapter) or the 12v rail of another computer's PSU.

As I said though, actually learn some basics about electricity before you go screwing around with your computers in this manner.