Can't record at the same level as my old tracks on old comp

Special Interest Groups Recording Techniques
2

You can use “Amplify” (in “Effect” menu) to make the amplitude (volume) of the old and new recordings the same.
Amplify to -0,2 in Audacity 1,3.png
Select the old track, apply amplify, then select the new track and apply amplify again.
The maximum (peak) amplitude on both tracks will then be the same.

If you are saving the file in the mp3 format you may need to set the amplify level (yellow box) to -1 or -2 db to prevent clipping (clicking) when it is converted to mp3.