A/C compressor not running?

Hi. I bought the car from a family who hadn't used it for a year and had given up on it. After replacing a door and the transmission, I was ready to sell it, but the A/C didn't work. It appeared to have no fluid, so I evacuated it and added a couple of ounces of oil. With one can of 134, I have 75lbs of pressure on both gauges, but the compressor won't kick in. I have spun it very slowly from the clutch with a screwdriver and it seems like it wants to go, but it doesn't. Bad clutch? Bad compressor? Something else that may prevent it from going.
I appreciate your help.
Charlie