Thinkpad 42 on startup screen is in a red pigment

This sounds like a display card (graphics card ) driver issue, or else the screen is going bad..

test that out by hooking up an external screen to the port on your laptop.. Then toggle using your function keys to use the external display..

If the external display allows you to see your desktop..

reload your graphics card driver, then boot up normally..

if the screen still doesnt work, you may need to replace it

Inverter going out. Get a new one. Common issue with t40 and 42