Using a little program called LogoMania* (sadly, no longer freeware), I have constructed a number of files that can be used to replace the tiresome old Windows cloud logo with the pulsing bar that appears when you start up Windows 95 and 98. Simply download the zip files of the logos you want (logo.sys files are essentially just bitmaps, so they take up too much space to be left unzipped), unzip them somewhere convenient and then copy one into the C drive root directory of your computer and rename it "logo.sys". It will make life easier if you rename the original Windows file "logo.old" or something similar before you do this. In order to change the logo, simply repeat the process with another one. Alternatively, use an installation program. Feel free to change the "Please wait while your computer shuts down" and "It is now safe to turn off your computer" files, called respectively "logow.sys" and "logos.sys", yourself. They can be replaced with any 320 by 400 pixel bitmap in 256 colour format and are usually stored in the Windows directory if they are not in C. Under absolutely no account screw around with any other ".sys" files. This will cause your computer to cease to function, but I'm sure you knew that.

*Other excellent logo utilities can be found at the XrX website here including a program that lets you view your logos without having to reset your screen settings to 256 colour, while easily correcting errors in the animation palette, and another that allows you to display logos as a screen saver. If you don't like the colours I've chosen for the cycling part of the image, you can change them with XrX to anything you please.

Here's a tip on using Logomania you won't find in the Help file: Windows places a border around the displayed start-up logo that is the same colour as the first palette position for the logo.sys file. Often this is some ugly colour that just happens to hold this position in the palette in the final graphic. The easiest way to ensure that this is a colour that works (which is to say, not very easy at all) is to change the first palette position for the "foreground" part of the logo image to the colour you want, prior to merging the foreground and background files in Logomania. How you do that without botching the image itself is up to you. With a totally animated image, you can change the colour manually in Logomania - just remember that this colour will animate along with the rest, so you'd better be sure it blends in.
Note also that the LogoMania program generates backgrounds in 2:3 proportion rather than the 4:5 proportions of the logo files. That is, circular backgrounds generated in LogoMania are actually oval when run as a start-up screen. Unless you want the final start-up screen to appear slightly distorted in the vertical (like some of my early ones are), always ensure that the graphic you shrink to 320 by 400 pixels is originally in the 4:3 proportions of the screen. You generally get better results shrinking the width and height as separate operations. All but a few of my early logos with this distortion problem have now been fixed.