That's the next thing I suppose, there Neo.
Alison. In your root directory (C:\) you will find two files called LOGOW.SYS and LOGOS.SYS.
Open either of these in PAINT and see if you can recognise the culprit!!!
You can probably find the original somewhere there, if not replace it with any 800x640 (256 colours) bitmap.
Or create one yourself and save it as one of the above names
My shutdown screen reads as "Turn me off now you b*****d"
B.