Thanks. Please see can you view multiple tracks simultaneous - #3 by Gale_Andrews to learn about the security risks of running XP.
What did you mean exactly when you said that did not work - that it recorded silence?
Assuming the 1/8 inch input is a microphone input which is only meant for weak signals, using the line out of the keyboard is likely to be worse than using the headphones output of the keyboard. The line out will be stronger than headphones out and you probably won’t be able to change the line out volume level.
If you have a blue line-in 1/8 inch computer input separate from the pink 1/8 inch mic input then you can definitely use the line-in, except for the echo when you hear yourself while recording.
I suggest you turn Transport > Software Playthrough off in Audacity. Open Sounds and Audio Devices, click “Volume” under “Sound playback” then see if there is a slider for the 1/8 inch input you are connecting to. If so, unmute that slider and turn it up and you’ll be able to hear yourself as you record without delay.
Gale