[cobalt-users] [RaQ550] Cannot boot suddenly --- How can I boot again?

["test1@xxxxxxx" <test1@xxxxxxx>]

Hello Cobalt people, 

For some reason my machine, Sun Cobalt RaQ550 was down.
 No matter how many times I tried rebooting, it always gets stuck at
 'Disk Checking' message on the front panel.
Is there any way of rebooting it in the 'Safe Mode' in Windows or like 
'Single User Mode'?
Reinstallation would finally be ok, but before all I wish to save part
 of important contents from the machine.

I've checked around the related information on he web using Google,
but so far I have not found useful ones.

Thank you for your asistance and instructions, 

Masa