My miter saw isn't cutting square anymore - help!
I am a very novice woodworker in the middle of a closet shelving project. Over the past day or so, my miter saw (a couple years old, lightly used) has started making unsquare cuts. I am using to cut straight down through wood on a 90 degree angle, no bevels or miters. The finished cut is a little bit off from 90 degrees. I haven't changed any of the settings.
I assume something has loosened up somewhere, but I'm not sure where to start. If I put a square between the fence and the blade, the blade is a tiny fraction off from square. I haven't adjusted anything so whatever it is came loose by itself. My instructions tell me I can adjust the blade parallel with the table or I can adjust the fence. Which one should I try, given that I haven't messed with either one yet. I tried unscrewing the fence a bit but the screws are very tight and won't budge, so I'm guessing the fence is tight and that maybe the blade is loose?
Any suggestions are welcome! I really want to finish this project but I can't if all my cuts are skewey! Help!