win 98 start-up problem

I have a compaq deskpro with windows 98.The system starts and runs fine up to the desktop screen.After the icons and all have loaded and the drive settles itself the screen goes blank and the computer seems to be in sleep mode.I did msconfig and unchecked everything in startup, but no help.It will operate in safe mode,but that provides no cd-rom so that I could run norton system works.Also scan disked and defraged.