This identification depends on parasitic diodes within the package. Assuming you have a digital multimeter, usually the red lead is positive with respect to the black lead when doing a diode test (confirm by reading the manual or by testing with a known diode).
If you test the leads relative to each other you should be able to identify one which tests as a diode (about 550-700mV reading on the meter) to each of the other two leads when forward biased and overrange when reverse biased). That will be the data lead.
Connect one of the other two leads to +5 through a 1K resistor and the remaining one to ground. Measure the voltage across the chip (ignore the data line). If it reads about 0.7V the GND and +5 are reversed. Swap the leads and measure again. If it reads more than about 1V that should be the correct +5 and Gnd connections. Do not use much less than 1K or the chip could be damaged.
You can then try connecting 5V and hope the smoke does not come out. Use a separate 5V supply, not your motherboard. When you connect it to your motherboard use the same polarity and at least temporarily put the 1K in series with the data line and preferably a polyswitch resettable fuse in series with the supply line to protect the motherboard.
No promises here, you may burn it out, or you could conceivably damage something else (such as the motherboard).
simulate this circuit – Schematic created using CircuitLab