I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

UPDATE:

The CMOS setting had NOTHING to do with the display issue.

The problem is that switch (turns off back light) when you close the
"lid" while the laptop is "running". Note: I NEVER close the "lid" until
after I shut down the laptop.

ANOTHER UPDATE:

At first, I thought that switch was the problem. I removed the button
type switch (normally open with "lid" up) thinking it was "leaky" (I have
seen this situation in some TVs I use to service).

The problem went away, but not for long.

Solution: I am now using an external monitor with this laptop.

John