The floppy disk is vital, and a X icon means that:
1: your disk has somehow gone bad
2: your floppy drive is dead (but I doubt it)
3: no bootable/corrupt System Folder on the disk (doubt it unless somebody was messing with the disk)
If you have another Macintosh equipped with a floppy drive, you can easily make a new boot disk with the disk images provided by Apple here.
If you don't have another Macintosh with a floppy drive, the most painless way out of the dilemma is here.
As Mars478 said, on startup, listen to the Macintosh SE for hard drive sounds. Do you hear the hard drive spinning up normally? Do you hear the hard drive struggling with spinning up? (the sounds will make it noticeable, and this is likely if the Macintosh SE has sat for a long time) Or do you not hear the hard drive spin up at all? If you hear the latter two, time for some troubleshooting.
And as for opening up your Macintosh SE, it's not that hard. You simply need a long-handled Torx T10 driver, which can be purchased at a home improvement store. Once you open up your Macintosh SE after letting the CRT discharge for a week or so, it is simply a matter of sourcing another 50-pin SCSI hard drive, carefully removing the original hard drive, removing the caddy, and installing your new hard drive into the caddy.
If the hard drive has trouble spinning up, try holding it in one hand and giving it a hefty smack on the top with the other, which should loosen up the stiction that the drive has developed if it has indeed been sitting for a long time.
Good luck!
-JRL
1: your disk has somehow gone bad
2: your floppy drive is dead (but I doubt it)
3: no bootable/corrupt System Folder on the disk (doubt it unless somebody was messing with the disk)
If you have another Macintosh equipped with a floppy drive, you can easily make a new boot disk with the disk images provided by Apple here.
If you don't have another Macintosh with a floppy drive, the most painless way out of the dilemma is here.
As Mars478 said, on startup, listen to the Macintosh SE for hard drive sounds. Do you hear the hard drive spinning up normally? Do you hear the hard drive struggling with spinning up? (the sounds will make it noticeable, and this is likely if the Macintosh SE has sat for a long time) Or do you not hear the hard drive spin up at all? If you hear the latter two, time for some troubleshooting.
And as for opening up your Macintosh SE, it's not that hard. You simply need a long-handled Torx T10 driver, which can be purchased at a home improvement store. Once you open up your Macintosh SE after letting the CRT discharge for a week or so, it is simply a matter of sourcing another 50-pin SCSI hard drive, carefully removing the original hard drive, removing the caddy, and installing your new hard drive into the caddy.
If the hard drive has trouble spinning up, try holding it in one hand and giving it a hefty smack on the top with the other, which should loosen up the stiction that the drive has developed if it has indeed been sitting for a long time.
Good luck!
-JRL