Microsoft has made these files hidden, system files so people coundn't find, and then change them. This is easy to fix though. Click Start -> Programs -> MS-DOS Prompt. Type ATTRIB -R -H -S C:\IO.sys press Enter and then type ATTRIB -R -H -S C:\LOGO.sys and press Enter again. Close the DOS Prompt. Now the files will be easy to access and work with.

Any of these screens can be replaced with an image created in MS Paint. First we're are going to try this trick with the start up screen. Open up Paint. Once it's open, select Image -> Attributes. A small dialog box will open. The first thing you have to change is the width. Erase whatever's in that box and type 320, and then change the height to 400. Make sure Pels is selected in the Units section and click OK.

Be creative, or maybe not so creative, if you just want to test this trick out.

Once you're all done with your creation click the File menu and then click Save. Where is says File name type c:\logo.sys and where is says Save as type choose 256 Color Bitmap. Your start up screen will not work at all if the file type is anything other than a 256 Color Bitmap. When you click save your computer will probably prompt you asking if you want to replace the existing file, select Yes. You may be thinking, "what If I don't like this, or I need to change it back?" good question, but that is why we chose the start up screen, because it, unlike the others has a backup, which is C:\IO.sys. Be careful though, if you delete IO.sys your computer will not work at all! Now, all that's left to do is restart your computer and see how it looks. If you decide that you don't like how it looks after you're done restarting, you can either edit the existing file, or creating a brand new one and saving it as c:\logo.sys, or just completely deleting the logo.sys file from your computer, so that the default Windows logo displays at startup.

The next screen you can customize is the screen that displays after you click Shut Down and you computer tells you that it's shutting down. With Windows 95 and 98 it's the same logo as the start up screen, except it says something to notify you that your computer is shutting down. Please proceed with caution, this screen does not have a backup. The file name is c:\windows\logow.sys, if you want to make your own backup of it. To change this file, follow the same steps as above, except this time save the file as c:\windows\logow.sys instead of c:\logo.sys.

The last screen is the the one that displays when your computer has finally finished shutting itself down. It has a black background with orange lettering and says "It is now safe to turn off your computer."
You might also like to make a backup of this one. To do so, follow the same steps before except use the file c:\windows\logos.sys. Likewise, for replacing it use the above steps, but use file name c:\windows\logos.sys.