boot error

Turned off my Sony laptop last night. Turned it on this
morning and windows would not boot. It gave me a message
that I either had a power failure or windows did not
close right. It said I needed to eith retry to "start
windows normally" Restart at the last point when there
was a good configuration. restart in Safe mode etc. I
tried al ooptions and each time it came back with the
following message. "stop:c0000221 unknown hard error
\systemroot\system32\ntdll.dll" Is there any way of
fixing this problem other than reformating my hard drive
and reinstalling all the recovery disks.