XPS 630, Vista 64 Boot Error

This is an inconsistant error and does not seem to be related to any hardware of software changes.  The log reads:

Problem signature:
  Problem Event Name:    BlueScreen
  OS Version:    6.0.6001.2.1.0.768.3
  Locale ID:    1033

Additional information about the problem:
  BCCode:    1000007e
  BCP1:    FFFFFFFFC0000005
  BCP2:    FFFFFA6000DB4AAB
  BCP3:    FFFFFA6002FE4E38
  BCP4:    FFFFFA6002FE4810
  OS Version:    6_0_6001
  Service Pack:    1_0
  Product:    768_1

Files that help describe the problem:
  C:\Windows\Minidump\Mini020209-01.dmp
  C:\Users\Mike\AppData\Local\Temp\WER-62150-0.sysdata.xml
  C:\Users\Mike\AppData\Local\Temp\WER1506.tmp.version.txt

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Start up repair is unable to correct the problem.  Sometimes the computer will start normally and sometimes I get this error.  Any ideas?

Thanks