Can a car alarm be installed in without power windows and doors?

Yes. Car alarms can be installed in cars without power windows and doors, although the installation may be more complex. Most car alarms involve securing sensors and wiring to various points within the vehicle, and if the car does not have power windows and doors, the installer may have to drill, route, or otherwise modify those areas in order to install the necessary sensors and wiring. For example, a tilt sensor (which detects changes in the vehicle's angle) may need to be mounted on the frame or undercarriage, and door and window sensors may need to be bypassed or connected to a different input. Nonetheless, with proper modifications and expertise, a car alarm can be installed in a car without power windows and doors.