Can’t get past login window

Hi my OS is windows 98SE and recently I’ve tried to turn my computer on but I can’t get past the login screen. After I press enter I get this error message “This program has performed an illegal operation and will shut down.

If the problem persist, contact the program vendor.”

when I click on the details button I recieve the following message.

“—Explorer caused an invalid page fault in module explorer.exe at 0167:00401f31.—”

If I close the window all I see is my background wallpaper and nothing more happens, the screen stays there and it doesn’t load anything else. Could some one please help me, I’d really appreciate it.