Re: Saw is not square?
There should be 4 bolts that hold the trunnion assembly to the underside of the table. You can loosen them and adjust the blade to the miter slot. Until you get this right on, all other adjustments don't count. Everything needs to be referenced TO the miter slot since it is the only thing that is not adjustable.
Also check to make sure the blade is not bent or wobbling due to a bent shaft or improperly machined faceplate on the shaft. If it is either, you will get a wrong reading every time you check the straightness of the blade to the miter slot. If you find the blade wobbling, you may need a dial indicator to check the wobble on the face plate that is on the shaft, where the blade goes up against. Some companies machine and thread the shaft, then press on the face plate. That is fine, but the plate MUST be re-surfaced true once it's pressed on. (learned that from a machinist buddy of mine.)
I like to first make 100% sure that the fence is exactly parallel to the miter slot before testing the blade straightness. (the longer the distance you can check, the better off you are. Checking from the front and back of the blade to the slot is not accurate enough for me.)
Once the fence is parallel to the slot and you have verified that the blade is running true, place a long metal bar (a good square works fine) against the blade, being careful not to catch odd teeth. If the blade has left and right leaning teeth, put the bar/square against two "right leaning" teeth. Then slowly move the fence towards the bar/square and check it. I keep mine within a few thousands of being parallel. Once the blade/trunnion are parallel to the miter slot, you are good to go.
Congratulations to Mr. "the sky is falling" Al Gore, nominated the new Village Idiot!