problem Disk Write Error

[Ron Cernokus <roncer@xxxxxxxxxxxxx>]

During the last couple of days my computer has started making a fairly
loud rhythmical clicking sound.
This has happened 2 to 3 times per day.  The sound generally lasts for
about 15 to 30 seconds. Twice the screen went blue and posted:

			        Disk Write Error
			 unable to write to disk in drive C:
			 Data or files may be lost.
			         press any key to continue  

When I press a key the blue screen disappears and everything seems OK.

Comments appreciated,
Ron