I purchased an older home and the ceiling fan in the bedroom has a resistor (I think) on the wall, it is a switch with a round knob to control the light and fan speed. Can I bypass this and control with the pull strings, as the fan in this room is newer.
You could bypass the switch but there is a code requirement for a light or outlet to be controlled by a switch. I would just leave the switch on. Note it is not a resistor but a solid state SCR or Triac that is adjusting the waveform, a very small resistor is used to vary the gate voltage to the SCR or Triac. If a resistor was used it would get very warm in the wall because the resistor would have to dissipate the heat, solid state controls turn the power off for part of the waveform.