How to convert BMP to 24 bit?

[VJsy...@america.com]

I have a visualization (Video Jockey) program that requires 24 bit BMP
files to be used. They are then internally converted into images
(within the VJ software), which are used as part of the visual
presentation. Converting any image to BMP is easy, but how in the hell
do I make it a 24 bit?

If that isn't bad enough, it can not exceed 90 colors, and the choices
are 16 or 256???????? 16 colors sucks, but 90 would work fine, if I
could find a way to reduce to 90.......

This has me puzzled beyond confusion.......

* I'm using PSP 5.01. (Yea, I know it's old, but it's easy to use,
unlike the latest bloated versions).

* I also have Photoshop 5 if that might help with this problem......

Can anyone help?

Thanks in advance.