Getting Event ID: 51 In Vista

Out of the blue i get this Event ID 51 in Vista.  it tells me to make sure that the dive is back-up. I have replaced the disk and still get the error. i did notice it happens when i down loading movies, I am not sure it that any to do with it.

The hardware is a IBM think pad T60 with 250 gigs of storage and a gig of ram

this is the event id
Log Name:      System
Source:        disk
Date:          1/29/2008 11:05:34 AM
Event ID:      51
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      Evilclownsho-PC
Description:
An error was detected on device \Device\Harddisk1\DR2 during a paging operation.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="disk" />
    <EventID Qualifiers="32772">51</EventID>
    <Level>3</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2008-01-29T16:05:34.310Z" />
    <EventRecordID>28099</EventRecordID>
    <Channel>System</Channel>
    <Computer>Evilclownsho-PC</Computer>
    <Security />
  </System>
  <EventData>
    <Data>\Device\Harddisk1\DR2</Data>
    <Binary>040168000100000000000000330004802D0100000E0000C00000000000000000000000000000000004AD0A0000000000FFFFFFFF01000000400000080000000000200A1280002040000000003C000000000000000835E5830000000098395A84688B1F84803104002A000004318000000800000000000000000000000000000000000000000000000000000000000000</Binary>
  </EventData>
</Event>