iexplore.exe application error

when i close explorer windows 7, a box comes up with the heading on the right
side of iexplore.exe application error. Below it reads: The instruction at
"0x749860" referenced memory at "0x00000000." The memory could not be "read".
Click on ok to terminate the progam. There is a gray box with the 0k on the
right hand bottom side of the box.

Can anyone help me with this problem. I went to the microsoft site, and
they did not know what the error was.
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kay L