First I would do the following..
1. Check to make sure there is no floppy disks in the sys.
2. Go to the bios make sure the cdrom is first boot device.
3. Then if is wasnt boot to the windows me cd and then reformat the system and then reinstall windows.
P.S. It is prob. that when you pressed ESC it was doing something to the boot files and they got correct and shit.... i would re format the hard drive and then you sould be able to reinstall windows.