I think I may have messed up the thermal compound that came with my Phenom processor. When I installed my processor's heat sink, I first barely laid it down and realized the wire was on the wrong side, so I picked it back up. I looked at it and there was a small smudge on it. Then, when I placed it down on the correct side, I realized it had not gone down straight. I had to rotate it a few degrees (maybe from 10:30 to 12:00). Is this an issue?
I don't want to power it up if it may overheat. Should I get some Arctic Silver and clean the old compound off and apply it?
Personally, I would say you are just fine, as along as your thermal paste is still intact on the CPU and heatsink.
My CPU cooler has a few degrees twisting play clockwise and counter-clockwise even when its fully tightend down(I guess it wasnt a perfectly designed clamping system) and I usally give it a little wiggle in each direction after securing it down to the motherboard, just to spread the TIM around nicely.