Vista - Explorer.exe stops running before my desktop is displayed

I've suddenly developed a problem when logging on to my laptop. Once I enter
my password, windows starts to load up, but explorer stops working before the
desktop or anything else is displayed, and produces an error message.
Clicking on the error message shuts the message down, but leaves a blank
black screen. I can load the task manager. I can also load Internet Explorer
by clicking on the 'privacy policy' hotlink at the foot of the error message.
Im running Vista Utlimate.
Any ideas?

The error massage displayed is..
'Windows Explorer has stopped working. Windows can check online for a
solution to the problem.'
Then two options.. 'Check online for a solution and close the program.' OR
'Close the program'.

The problem details are as follows..
Problem signature:
Problem Event Name: BEX
Application Name: Explorer.EXE
Application Version: 6.0.6001.18000
Application Timestamp: 47918e5d
Fault Module Name: StackHash_fd00
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Offset: 01890090
Exception Code: c0000005
Exception Data: 00000008
OS Version: 6.0.6001.2.1.0.256.1
Locale ID: 5129
Additional Information 1: fd00
Additional Information 2: ea6f5fe8924aaa756324d57f87834160
Additional Information 3: fd00
Additional Information 4: ea6f5fe8924aaa756324d57f87834160

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