hard disk controller error

ive got a computer getting this error in the system log files.  it has been logging repeatedly for many days now.
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Event Type:      Error
Event Source:      Disk
Event Category:      None
Event ID:      11
Date:            11/10/2005
Time:            9:39:11 AM
User:            N/A
Computer:      SECURE
Description:
The driver detected a controller error on \Device\Harddisk1\DR1.
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i am also getting another couple errors that are related, but these arent happening nearly as often.
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Event Type:      Warning
Event Source:      Ftdisk
Event Category:      None
Event ID:      50
Date:            11/10/2005
Time:            9:18:08 AM
User:            N/A
Computer:      SECURE
Description:
{Lost Delayed-Write Data} The system was attempting to transfer file data from buffers to \Device\HarddiskVolume2. The write operation failed, and only some of the data may have been written to the file.
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Event Type:      Information
Event Source:      Application Popup
Event Category:      None
Event ID:      26
Date:            11/10/2005
Time:            9:18:08 AM
User:            N/A
Computer:      SECURE
Description:
Application popup: Windows - Delayed Write Failed : Windows was unable to save all the data for the file \Device\HarddiskVolume2\Program Files\NexSentry Manager\Database. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere.
=====================
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Event Type:      Error
Event Source:      Disk
Event Category:      None
Event ID:      7
Date:            11/9/2005
Time:            3:54:25 PM
User:            N/A
Computer:      SECURE
Description:
The device, \Device\Harddisk1\DR1, has a bad block.
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it looks to me like the hard drive is going out.  before i replace it though, i just want to make sure that these error arent being caused by the motherboard.  the computer is a dell precision 340.  i was just told that this computer should have a scsi drive, so is it possible that the scsi controller is causing these errors? i cannot even open the disk management to see anything about the disks.  it gives me an error box instructing me to check the logs.